Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology最新文献

{"title":"Molecular characterization and functional divergence of igfbp3a and igfbp3b in turbot (Scophthalmus maximus)","authors":"Yujie Yu ,&nbsp;Feixia Li ,&nbsp;Feng Wang ,&nbsp;Yudong Jia","doi":"10.1016/j.cbpa.2026.111980","DOIUrl":"10.1016/j.cbpa.2026.111980","url":null,"abstract":"<div><div>Insulin-like growth factor binding protein 3 (IGFBP3), an important member of the IGFBP family, is involved in growth, reproduction and metabolic regulation. In the present study, we isolated and characterized two IGFBP3 subtypes, namely IGFBP3a and IGFBP3b from turbot through rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR) cloning. The deduced amino acid sequences of turbot IGFBP3a and IGFBP3b showed high homology to those of other teleosts, particularly with Atlantic halibut (<em>Hippoglossus hippoglossus</em>). Turbot IGFBP3a and IGFBP3b contained two conserved motifs in the IGFBP domain (GCGCCXXC) and thyroglobulin type 1 domain (CWCV) as well as conserved cysteines. Molecular docking analysis predicted that IGFBP3a preferentially bound to IGF3, whereas IGFBP3b preferentially bound to IGF1. Both proteins localized in the cytoplasm and nucleus. The <em>igfbp3a</em> mRNA was most abundant in the livers of males and the pituitary of females, followed by the pituitary and heart in males, and the ovaries in females. However, <em>igfbp3b</em> was abundant in the hearts of males and females. <em>igfbp3a</em> and <em>igfbp3b</em> mRNAs significantly increased from the two-cell stage to the gastrula stage, peaked at gastrulation, and sharply decreased at the hatched larval stage. Moreover, the mRNA level of <em>igfbp3a</em> was significantly higher than that of <em>igfbp3b</em> throughout turbot embryonic development. These findings suggested functional divergence between IGFBP3a and IGFBP3b, IGFBP3a may play a key role during embryonic development and tissue-specific modulation in turbot.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"314 ","pages":"Article 111980"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146133697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Voltage-gated K+ channels modulate the neural abiotic stress tolerance of Drosophila melanogaster","authors":"Mads Kuhlmann Andersen ,&nbsp;Dawson B.H. Livingston ,&nbsp;R. Meldrum Robertson ,&nbsp;Heath A. MacMillan","doi":"10.1016/j.cbpa.2026.111969","DOIUrl":"10.1016/j.cbpa.2026.111969","url":null,"abstract":"<div><div>Severe abiotic stress causes insects to lose nervous function and enter a state of paralytic coma. Central to this loss of function is a spreading depolarization (SD), where a characteristic collapse of ion gradients depolarizes neuronal and glial membranes and rapidly shuts down the CNS. Despite representing a critical limit to CNS function, the stress threshold that elicits SD can be altered by the process of acclimation and the mechanisms underlying this response remain largely unknown. Here, we made electrophysiological measurements of SD and investigated the role of voltage-gated K⁺ channels in acclimation of the CNS stress response of <em>Drosophila melanogaster</em>. First, we demonstrate that improved cold tolerance in the CNS elicited by cold acclimation was dampened by pharmacological blockade of voltage-gated K⁺ channels. Next, we used the Gal4/UAS model system to screen for candidate genes encoding glial voltage-gated K⁺ channels and found that knockdown of <em>sei</em>- and <em>Shaw</em>-encoded channels mimicked the effect of channel blockade. Furthermore we show that the knockdown of glial <em>sei</em>-encoded channels also impairs tolerance to anoxia and heat stress. These findings suggest that voltage-gated K⁺ channels, especially those encoded by <em>sei</em>, are integral to the CNS stress resistance and are likely involved in the acclimation response, and we posit that this could relate to mechanisms involving glial spatial buffering and barrier function. Establishing links between tissue-specific expression of candidate genes and SD mechanisms will inevitably aid our understanding of insect ecophysiology and SD-related neuropathologies.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111969"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146013376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Endogenous trade-offs among organs across seasonal reproductive states in the spotted munia (Lonchura punctulata)","authors":"Shirin Fatima ,&nbsp;Sayantan Sur ,&nbsp;Jyoti Tiwari ,&nbsp;Vikas Yadav ,&nbsp;Mihir Kumar ,&nbsp;Aakansha Sharma ,&nbsp;Sangeeta Rani ,&nbsp;Shalie Malik","doi":"10.1016/j.cbpa.2026.111967","DOIUrl":"10.1016/j.cbpa.2026.111967","url":null,"abstract":"<div><div>Annual reproductive processes are timed by the endogenous circannual clock and environmental cues. Although seasonal phenotypic plasticity is well-documented in birds, the endogenous changes in organ size and histomorphometry are less characterized. The current experiment was designed to investigate the annual changes in reproductive, metabolic, and immune organs across reproductive states under constant environmental conditions. To address this question, we chose the spotted munia, a subtropical passerine finch, which shows robust circannual rhythmicity under captivity. Munias (<em>N</em> = 15 Males +15 Females) were kept under equinox photoperiod (12 L: 12D, L = Light, ∼1.86 W/m²; D = Dark, &lt;0.00014 W/m²) with constant temperature (22 ± 2 °C) and humidity (58 ± 2 %) for ∼9 months. Laparotomy was performed to identify annual reproductive states, including pre-breeding, breeding, and the onset of regression phase (<em>N</em> = 5 Males +5 Females, each group), in which morphometry and histological assays were conducted. We observed body fattening, elevated heterophil-to-lymphocyte (H/L) ratio, gonadal recrudescence, and muscle fibre growth, along with splenic atrophy during the breeding phase. Principal component analysis revealed that reproductive and metabolic traits clustered together and traded off against immune traits, while body mass and intestine length loaded on a separate axis. Overall, our data demonstrate the presence of endogenously regulated trade-offs in physiology and histology, highlighting the role of circannual clocks in directing avian life-history strategies.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111967"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145936483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Life without air: Metabolic responses of the tree frog Boana pulchella under anoxic conditions","authors":"Marjoriane de Amaral ,&nbsp;Gustavo Kasper Cubas ,&nbsp;Rafaella Sanfelice Normann ,&nbsp;Jorge Felipe Argenta Model ,&nbsp;Bruna Selau ,&nbsp;Guendalina Turcato Oliveira ,&nbsp;Luiz Carlos Kucharski","doi":"10.1016/j.cbpa.2026.111974","DOIUrl":"10.1016/j.cbpa.2026.111974","url":null,"abstract":"<div><div>Amphibians possess intricate biochemical and physiological adaptations that enable survival in oxygen-deprived environments. Our study investigated metabolic and oxidative responses in the brain, skeletal muscle, liver, and plasma of the subtropical tree frog <em>Boana pulchella</em> exposed to 30 min of anoxia followed by normoxic recovery. Adult males were divided into control, anoxia, and recovery groups (<em>n</em> = 5 each). Key parameters measured included gluconeogenesis from lactate, catalase (CAT) and superoxide dismutase (SOD) activities, thiobarbituric acid reactive substances (TBARS), glucose oxidation, glycogen synthesis, and plasma and tissue metabolite levels. Plasma glucose, urea, and hemoglobin concentrations were stable, whereas plasma lactate increased significantly during anoxia (65% vs. control; 41% vs. recovery), confirming activation of anaerobic metabolism. In skeletal muscle, protein and urea concentrations were significantly higher in the recovery group compared to anoxia, indicating post-stress metabolic reactivation. In the liver, glucose oxidation increased by ∼66% and glycogen synthesis by ∼70% during anoxia, suggesting anticipatory energy storage, while brain gluconeogenesis from lactate declined nearly twofold, pointing to preferential lactate utilization as fuel. Antioxidant enzyme activities remained stable across tissues; however, hepatic TBARS increased ∼3.6-fold during anoxia compared to control, although this difference was not statistically significant, indicating a possible tendency toward oxidative imbalance. Principal component analyses revealed tissue-specific metabolic signatures: plasma responses driven by lactate and hemoglobin, liver by protein and TBARS, muscle by protein and urea, and brain by protein and urea. Together, these findings demonstrate that <em>Boana pulchella</em> maintains systemic stability under short-term anoxia through tissue-specific metabolic adjustments, with the liver acting as a central hub for energy regulation and the brain displaying metabolic flexibility to sustain function during oxygen deprivation.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111974"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146047439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated transcriptomic and proteomic analyses reveal the physiological stress responses and adaptive mechanisms of Macrobrachium nipponense to carbonate alkalinity","authors":"Yiming Li ,&nbsp;Chenxi zhu ,&nbsp;Zongli Yao ,&nbsp;Pengcheng Gao ,&nbsp;Yan Li ,&nbsp;Kai Zhou ,&nbsp;Qichen Jiang ,&nbsp;Qifang Lai","doi":"10.1016/j.cbpa.2026.111970","DOIUrl":"10.1016/j.cbpa.2026.111970","url":null,"abstract":"<div><div>To explore the effect of carbonate alkalinity stress on the East Asian river prawn (<em>Macrobrachium nipponense</em>), specimens were cultured at three alkalinity levels (0, 10, and 20 mmol/L NaHCO₃) for 96 h. We employed integrated transcriptomic and proteomic analyses to investigate the molecular mechanisms involved in the stress response of shrimp muscle tissue to alkalinity stress. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed significant involvement of the “Protein processing in endoplasmic reticulum” pathway across both omics datasets, with consistent downregulation of key components such as oligosaccharyltransferases and heat shock protein 70, suggesting potential endoplasmic reticulum stress. Additionally, both transcriptomic and proteomic data showed activation of metabolic pathways including glycolysis and the pentose phosphate pathway (PPP) under alkaline stress. This metabolic shift serves as a vital compensatory strategy to supply the substantial ATP required for active ion transport to maintain intracellular pH stability, and to provide NADPH for antioxidant systems to counteract oxidative damage.Oxidative stress was further evidenced by changes in expression of antioxidant-related genes (e.g., <em>peroxisomal biogenesis factor</em>, <em>superoxide dismutase</em>, <em>peroxiredoxin-5</em>, <em>xanthine dehydrogenase</em>), altered expression of proteins involved in lipid metabolism and reactive oxygen species processing (e.g., long-chain acyl-coenzyme A synthase, 3-hydroxy-3-methylglutaryl-CoA lyase), and elevated levels of catalase activity and malondialdehyde content. Alkalinity stress also damaged the tissue structure of the hepatopancreas. These findings demonstrate that alkalinity induces oxidative stress and activates antioxidant defense mechanisms in <em>M. nipponense</em>. The results of this study provide a theoretical basis for further research on the adaptive mechanisms of freshwater shrimp in saline-alkali water farming.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111970"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146013388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A potential antioxidant role for melatonin and AFMK in plasma, ovarian fluid, and eggs during reproduction in rainbow trout","authors":"Konrad Pomianowski ,&nbsp;Magdalena Gozdowska ,&nbsp;Stefan Dobosz ,&nbsp;Rafał Różyński ,&nbsp;Ewa Kulczykowska","doi":"10.1016/j.cbpa.2026.111976","DOIUrl":"10.1016/j.cbpa.2026.111976","url":null,"abstract":"<div><div>Melatonin (Mel; <em>N</em>-acetyl-5-methoxytryptamine) is recognized in fish as both a biological time-keeper and regulator of many physiological processes, including reproduction. Beyond its endocrine functions, Mel acts as an antioxidant, either by directly scavenging reactive radicals and forming N¹-acetyl-N²-formyl-5-methoxykynuramine (AFMK), or by influencing the activity of antioxidant enzymes. This study examined whether Mel contributes to the protection of post-ovulated eggs of farmed rainbow trout against oxidative stress. Mel and AFMK levels were measured in plasma, ovarian fluid, and eggs, while the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) were determined in eggs. Plasma Mel concentrations did not significantly differ among pre-ovulation, ovulation, and post-ovulation stages, nor did they correlate with ovarian fluid levels. AFMK was undetectable in both plasma and ovarian fluid, whereas both Mel and AFMK were consistently present and positively correlated in eggs. This suggests that Mel directly reacts with reactive oxygen species within the eggs, resulting in AFMK formation. Mel concentrations in eggs did not correlate with the activities of SOD, CAT, or GST, implying that Mel primarily contributes to the antioxidant defense of post-ovulated eggs through non-enzymatic radical scavenging. Mel and AFMK levels were lower in eggs from four-year-old females compared to three-year-old, whereas SOD activity showed the opposite trend, suggesting a compensatory upregulation of enzymatic defense mechanisms in response to an age-related Mel decline. The concentration of Mel in eggs was approximately three times higher than in plasma or ovarian fluid, suggesting possible local synthesis within oocytes.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111976"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146097627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gonadic cycle and environmental modulation of P450 aromatase localization in Cerastoderma glaucum ovary from Monastir Bay","authors":"Imen Hmidi ,&nbsp;Lorenzo Riccio ,&nbsp;Teresa Chianese ,&nbsp;Latifa Knani ,&nbsp;Luigi Rosati ,&nbsp;Leila Hmida","doi":"10.1016/j.cbpa.2026.111966","DOIUrl":"10.1016/j.cbpa.2026.111966","url":null,"abstract":"<div><div>The gonadic cycle of bivalve molluscs is highly variable and depends on several factors, including the geographical location and environmental conditions of the populations. The aim of this study was to analyse the gonadic cycle of <em>Cerastoderma glaucum</em> female by monitoring a population sampled in Monastir Bay (Tunisia) over a period of 13 months, correlating histological analyses of the ovary with environmental parameters. In addition, we studied the localisation of P450 aromatase, a key enzyme involved in the biosynthesis of 17β-estradiol, to understand its possible role in regulating the oogenesis process. Histological analysis of the ovary revealed the constant presence of oocytes at different stages of maturation, suggesting an asynchronous reproductive cycle, in which the reproductive phase of <em>C. glaucum</em> is continuous throughout the year, without periods of quiescence, and is characterized by three main reproductive events: one in spring, the most significant in summer and a final one in autumn. Environmental factors such as temperature appear to support the progression of gametogenesis, while salinity appears to influence the gamete release phase. Finally, the distribution of aromatase showed a clear correlation with oocyte maturation stages, suggesting a direct involvement of the enzyme in the progression of the female gonadal cycle. Aromatase expression therefore appears to respond to environmental changes, such as variations in water temperature, suggesting a possible mechanism of environmental regulation of reproductive function.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111966"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hematopoietic and molecular responses of largemouth bass (Micropterus salmoides) to chronic heat stress","authors":"Yichuan Lin ,&nbsp;Zhicong Zhang ,&nbsp;Jiahao Zhang ,&nbsp;Wenjing He ,&nbsp;Yan Zhou ,&nbsp;Songqian Huang ,&nbsp;Shouwen Jiang ,&nbsp;Wanying Zhai ,&nbsp;Qianghua Xu","doi":"10.1016/j.cbpa.2026.111973","DOIUrl":"10.1016/j.cbpa.2026.111973","url":null,"abstract":"<div><div>With global climate warming increasingly threatening aquatic ecosystems, prolonged exposure to high temperatures has become a major environmental stressor for both wild and cultured fish. However, the long-term effects of chronic heat stress on blood physiology and hematopoietic processes remain poorly understood. To assess the long-term impacts of chronic heat stress on hematopoiesis in largemouth bass (<em>Micropterus salmoides</em>), we conducted a 180-day acclimation experiment at 34 °C. Hematological analyses showed significant reductions in red blood cell counts and hemoglobin concentrations, indicating impaired oxygen transport capacity. Blood cell morphology was altered, with erythrocytes exhibiting a lower major-to-minor axis ratio and leukocytes (lymphocytes and granulocytes) showing increased volumes. Histological and ultrastructural observations of the head kidney revealed tissue loosening, hemosiderin deposition, mitochondrial damage, and elevated apoptosis. Furthermore, transcriptomic analysis combined with GO and KEGG enrichment revealed that pathways involved in vascular development, stress response, and fatty acid metabolism were significantly activated under heat stress. Notably, key genes associated with angiogenesis, lipid metabolism, stimuli response, apoptosis and immunity, including <em>mmp9</em>, <em>angptl4</em>, <em>abca1</em> and <em>stab2</em>, were markedly upregulated, suggesting their crucial roles in vascular remodeling and thermotolerance. Together, these results provide the first integrative cellular and molecular characterization of hematopoietic responses to prolonged high temperature in <em>M. salmoides</em>. The findings enhance understanding of fish physiological plasticity under environmental stress and have implications for aquaculture management and the development of heat-resilient strains.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111973"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146108364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methods: Long-term stability of autonomic and cardiovascular regulation in a decerebrate snake model","authors":"Driele Tavares ,&nbsp;Samanta Aparecida Castro ,&nbsp;Edwin William Taylor ,&nbsp;Cléo Alcantara Costa Leite","doi":"10.1016/j.cbpa.2026.111971","DOIUrl":"10.1016/j.cbpa.2026.111971","url":null,"abstract":"<div><div>A recently developed decerebrate preparation of the rattlesnake, <em>Crotalus durissus,</em> has enabled simultaneous recordings of cardiovascular and respiratory variables, whilst preserving aspects of their control by the autonomic nervous system. However, its reliability for more extended experimental protocols requires further validation of the extent of recovery and temporal stability of autonomic modulation, after decerebration. Here we monitored the recovery of cardiovascular and autonomic variables, checking their temporal stability of autonomic modulation for up to 15 days post-decerebration and assessed their responsiveness to different levels of anesthesia. Cardiovascular variables—including heart rate, stroke volume, cardiac output, systemic and pulmonary arterial pressures, blood flows, conductances, and cardiac shunt—remained stable and comparable to values reported for both intact and previously decerebrated snakes throughout the extended experimental period. Also, both autonomic indexes HRV and baroreflex were operational and consistent across recordings. Additionally, graded increments of anesthesia (isoflurane) produced incremental cardiovascular effects. The maintenance of cardiovascular and autonomic modulation of this wide range of interrelated variables in the decerebrated preparation confirms its adequacy for investigating these systems in long-term experimental protocols.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111971"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146055002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Not the cAMP/PKA pathway but the cGMP/PKG pathway promotes branchial ammonia excretion in the green shore crab, Carcinus maenas","authors":"Baoyue Zhang,&nbsp;Dirk Weihrauch","doi":"10.1016/j.cbpa.2026.111968","DOIUrl":"10.1016/j.cbpa.2026.111968","url":null,"abstract":"<div><div>Ammonotelic animals excrete their toxic waste ammonia directly into the surrounding environment. To deal with conditions causing elevated hemolymph ammonia levels, such as feeding, an efficient ammonia excretion process must be in place to keep hemolymph ammonia levels within a tolerable range. Although the actual ammonia excretion mechanisms in fish and crustaceans have been investigated extensively, the intracellular regulation of these processes is more or less unknown. To investigate the involvement of the cAMP/PKA and cGMP/PKG pathway in the branchial excretion process, gills from osmoregulating green shore crabs, <em>Carcinus maenas,</em> were isolated and perfused with solutions containing either 200 or 500 μmol L⁻¹ NH₄Cl, mimicking the hemolymph ammonia levels in the resting state and after feeding, respectively. Basolateral application of forskolin or 8-Bromo-cAMP caused a significant decrease in the ammonia excretion rate. Moreover, cAMP activation caused an increase in metabolically generated ammonia, of which the majority was now transported towards the hemolymph side and not, as seen under control conditions, into the environment. This suggests that cAMP/PKA pathway promotes a so far not described ammonia retention mechanism. In contrast, activating the cGMP/PKG pathway by 8-Bromo-cGMP resulted in an increase of the transbranchial ammonia excretion rate, which could be partially inhibited by the PKG blocker KT5823. Participation of branchial expressed nitric oxide synthase in cGMP synthesis via the soluble guanylyl cyclase is suggested due to the observed inhibitory effect after the application of L-NAME. This study opens a new venue of investigations regarding epithelial ammonia transport regulation in animal systems.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"313 ","pages":"Article 111968"},"PeriodicalIF":2.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145949395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}