Comparative biochemistry and physiology. C: Comparative pharmacology最新文献

{"title":"Characterization of α1-adrenoceptors which mediate chronotropy in neonatal rat cardiac myocytes","authors":"Hisakazu Kimura ,&nbsp;Atsushi Miyamoto ,&nbsp;Shin Kawana ,&nbsp;Hideyo Ohshika","doi":"10.1016/0742-8413(93)90089-4","DOIUrl":"10.1016/0742-8413(93)90089-4","url":null,"abstract":"<div><p>1. In the present study, we investigated the effect of culture on <em>α</em>₁-adrenoceptors that mediate chronotropy and on <em>α</em>₁-adrenergic signal transduction in neonatal rat cardiac myocytes.</p><p>2. The spontaneous beating rate of neonatal rat myocytes after 3 or 7 days in culture was 37.4 ± 4.2 or 102.0 ± 4.3 beats min⁻, respectively. The <em>α</em>₁-adrenoceptor-mediated chronotropic effect of norepinephrine was positive at day 3 of culture. In contrast to day 3 of culture, the neonatal myocytes exhibited a negative chronotropic response to norepinephrine on day 7 of culture. Both of these effects of norepinephrine were completely abolished by prazosin.</p><p>3. The affinity (<em>K</em>_d) and/or density (<em>B</em>_max) of <em>α</em>₁-adrenoceptors labeled with [³H]prazosin in membranes from cultured myocytes were not significantly different between day 3 and day 7 of culture.</p><p>4. The expression of G_s, G_i, G_q and G_o, α-subunits in membranes from cultured myocytes was found to be significantly increased with the passage of culture time by immunoblot analysis. In contrast, no significant differences in G_β-subunit expression were observed between day 3 and day 7 of culture.</p><p>5. Norepinephrine-stimulated inositol 1,4,5-trisphosphate production by radio-binding protein in neonatal myocytes after 7 days of culture was significantly higher than that of the day 3 counterpart.</p><p>6. No significant changes in phospholipid and cholesterol contents in membranes from neonatal myocytes were observed with longer culture times.</p><p>7. These results suggest that changes in the responsiveness to <em>α</em>₁-adrenergic stimulation from positive to negative chronotropy during culture of cardiac myocytes are mediated, at least in part, by functional alterations in the <em>α</em>₁-adrenergic signal transduction systems, including both G-protein expression and inositol 1,4,5-trisphosphate production.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 479-485"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90089-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18901044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increased 5-aminolevulinic acid (ALA) in heavy metal exposed bivalve molluscs, Cerastoderma edule: An effect due to inhibition of porphobilinogen synthase?","authors":"V. Brock ,&nbsp;A. Brock","doi":"10.1016/0742-8413(93)90091-X","DOIUrl":"10.1016/0742-8413(93)90091-X","url":null,"abstract":"<div><p>1. The effect of cadmium, lead, and mercury on 5-aminolevulinic acid (ALA), porphobilinogen (PBG), and PBG synthase was determined in hepatopancreas of the bivalve, <em>Cerastoderma edule</em> (L.).</p><p>2. Cd and Hg exposure induced increased ALA content, and thus an initial doubling of ALA within 24 hr.</p><p>3. Using ALA in excess (8 mmoll⁻¹) as substrate, no PBG synthase (ALA dehydratase, EC 4.2.1.24) activity was detectable in freshly prepared hepatopancreas homogenates.</p><p>4. Increased ALA in metal exposed bivalves is not a simple effect due to metal inhibition of PBG synthase.</p><p>5. The observed lack of PBG synthase suggests an alternative to the general pathway where two ALA molecules condense to one PBG.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 493-499"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90091-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54006483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vivo evaluation of reuterin and its combinations with suramin, melarsoprol, dl-α-difluoromethylornithine and bleomycin in mice infected with Trypanosoma brucei brucei","authors":"Manasses K. Yunmbam,&nbsp;John F. Roberts","doi":"10.1016/0742-8413(93)90095-3","DOIUrl":"10.1016/0742-8413(93)90095-3","url":null,"abstract":"<div><p>1. <em>Trypanosoma brucei brucei</em> -infected mouse models treated with a new antibiotic, reuterin, showed reduction of the levels of parasitemia and prolonged survival of the mice.</p><p>2. Cures of the parasitemia were observed in groups of mice treated with combinations of reuterin and suramin or melarsoprol.</p><p>3. Reuterin administered in combination with bleomycin or <span>dl</span>-α-difluoromethylornithine showed temporary remission of the parasitemia in groups of mice.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 521-524"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90095-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18696041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vivo adaptative regulation of muscarinic receptors and muscarinic stimulation-induced Ca2+ mobilization during short-term heat exposure in rat parotid glands","authors":"H. Fujinami ,&nbsp;K. Komabayashi ,&nbsp;T. Izawa ,&nbsp;K. Suda ,&nbsp;M. Tsuboi","doi":"10.1016/0742-8413(93)90085-Y","DOIUrl":"10.1016/0742-8413(93)90085-Y","url":null,"abstract":"<div><p>1. Adaptation of muscarinic receptors (MR)—muscarinic stimulation—induced intracellular Ca²⁺ mobilization during short-heat exposure (33°C).</p><p>2. Heat-exposure for 48 hr decreased the carbachol (CCh)-stimulated cytosolic C²⁺ concentration increase.</p><p>3. The number of MR on cell surface increased transiently at 24 hr with a subsequent decrease at 48 hr.</p><p>4. CCh-stimulated inositol trisphosphate (IP₃) formation decreased at 48 hr.</p><p>5. In saponin-permeabilized cells, 1,4,5-IP₃-induced ⁴⁵Ca²⁺ release decreased at 24 hr.</p><p>6. The data suggest that the adaptation for increased muscarinic stimulation occurs at IP₃ generating sites as well as at intracellular IP₃ receptor sites during heat exposure.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 451-457"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90085-Y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18901042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cholera toxin: Radio-iodination and uptake by the intestine of suckling rats","authors":"Aye-Kyaw,&nbsp;Khin Thandar Win,&nbsp;Lei Lei Oo,&nbsp;Tin Oo","doi":"10.1016/0742-8413(93)90077-X","DOIUrl":"10.1016/0742-8413(93)90077-X","url":null,"abstract":"<div><p>1. The chloramine-T procedure was employed to radio-iodinate cholera toxin using Na¹²⁵I. The procedure was found to be efficient and reproducible.</p><p>2. Intragastric injections of both the labelled and the unlabelled toxin produced (a) significant increases in intestinal fluid accumulation as measured by the fluid accumulation ratio; (b) significant increases in cAMP levels; and (c) significant decreases in cAMP-phosphodiesterase activities when compared with the controls suggesting that radio-iodination did not impair the biological activity of the toxin.</p><p>3. <em>In vivo</em> uptake studies of the labelled toxin by different parts of the intestine indicated that the uptake by the duodenum and jejunum was high and rapid when compared with the ileum implying that there are more binding sites (or receptor proteins) for cholera toxin in the duodenum and jejunum than in the ileum.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 397-400"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90077-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18897674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of formamidines on batrachotoxin in a 20α-benzoate binding to neural membranes from pyrethroid susceptible and resistant tobacco budworm moths Heliothis virescens","authors":"C.J. Church,&nbsp;S.F. Abd-Elghafar,&nbsp;C.O. Knowles","doi":"10.1016/0742-8413(93)90084-X","DOIUrl":"10.1016/0742-8413(93)90084-X","url":null,"abstract":"<div><p>1. Amitraz stimulated [³H]batrachotoxin in A 20-α-benzoate ([³H]BTX-B) binding to neural membranes from pyrethroid susceptible (S) and resistant (R) tobacco budworm moths, but <em>N</em>′-(2,4-xylyl)-<em>N</em>-methylformamidine (SN 49844) stimulated binding only with S moths.</p><p>2. Chlordimeform stimulated [³H]BTX-B binding only with R moths, and <em>N</em>-(4-chloro-<em>o</em>-tolyl)-<em>N</em>-methylformamidine (demethylchlordimeform) yielded no significant stimulation with either strain.</p><p>3. A mixture of amitraz and deltamethrin, a pyrethroid that previously had been shown to enhance [³H]BTX-B binding with tobacco budworm moths, also gave significant stimulation of radioligand binding with S moths.</p><p>4. When membranes were prepared from S moths at various intervals following topical application of amitraz, deltamethrin, or a mixture of amitraz and deltamethrin, biphasic stimulation of [³H]BTX-B binding was observed, with maximum enhancement occurring at 2 and 6 hr.</p><p>5. These results provided a basis for suggesting that a formamidine binding site is located on or closely associated with the sodium channel protein.</p><p>6. Whether this site is the same as the pyrethroid/DDT binding domain remains to be demonstrated; however, similarities in responses elicited by amitraz and deltamethrin alone and in combination indicate that some relationship may exist.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 443-449"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90084-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54006424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of gradual water acidification on the oxygen consumption pattern of fish","authors":"Peter L.M. Van Dijk ,&nbsp;Guido E.E.J.M.Van Den Thillart ,&nbsp;Sjoerd E. Wendelaar Bonga","doi":"10.1016/0742-8413(93)90081-U","DOIUrl":"10.1016/0742-8413(93)90081-U","url":null,"abstract":"<div><p>1. Carp (<em>Cyprinus carpio</em>) and tilapia (<em>Oreochromis mossambicus</em>) were kept in a flow-through respirometer for a week, while continuous oxygen consumption measurements were carried out, at a constant water O₂ concentration.</p><p>2. Our measurements showed that tilapia decreased its standard metabolic rate (SMR), its average oxygen consumption, and its maximum metabolic rate in acid water (pH 4.0), whereas carp did not.</p><p>3. It is proposed, based on our results, that carp and tilapia probably have different strategies to survive pH depression episodes: whereas tilapia avoids the additional stress of exercise, carp tries to escape the acid conditions.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 421-427"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90081-U","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54006406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of several peptides with pro-arg-leu-NH2 C-terminal sequence on invertebrate muscles","authors":"Y. Fujisawa ,&nbsp;T. Ikeda ,&nbsp;T. Takahashi ,&nbsp;Y. Furukawa ,&nbsp;Y. Muneoka ,&nbsp;S. Matsumoto ,&nbsp;H. kuniyoshi ,&nbsp;A. suzuki","doi":"10.1016/0742-8413(93)90088-3","DOIUrl":"10.1016/0742-8413(93)90088-3","url":null,"abstract":"<div><p>1. Effects of the following PRLamide peptides on some invertebrate muscles were examined: APNFLAYPRLamide (a peptide of the bivalve mollusc <em>Mytilus</em>), AAPLPRLamide (a peptide of the echiuroid <em>Urechis</em>), FTPRLamide (a fragment of a peptide of the insect <em>Pseudaletia</em>), YFSPRLamide (a fragment of a peptide of the insect <em>Heliothis</em>) and pQTSFTPRLamide (a peptide of the insect <em>Leucophaea</em>).</p><p>2. In the ABRM of <em>Mytilus</em>, the <em>Mytilus</em> and <em>Urechis</em> peptides potentiated phasic contraction by repetitive electrical stimulation. The former was more potent than the latter. The three insect-origin peptides did not show any potentiating effect but showed a weak antagonistic action on the potentiating effect of the <em>Mytilus</em> peptide. Except the <em>Mytilus</em> peptide, the PRLamide peptides showed little or no relaxing effect on catch tension, though they accelerated catch-relaxing response to repetitive electrical stimulation.</p><p>3. In the inner circular body-wall of muscle of <em>Urechis</em>, the PRLamide peptides showed a potentiating effect on twitch contraction. The <em>Urechis</em> peptide was most potent. In the esophagus of the annelid <em>Perinereis</em>, the PRLamide peptides showed a contractile effect. The <em>Urechis</em> peptide was also most potent.</p><p>4. In the crop of the cricket <em>Gryllus</em>, the insect-origin peptides markedly potentiated spontaneous rhythmic contractions. The <em>Mytilus</em> peptide showed a weak potentiating effect, but the <em>Urechis</em> peptide showed little or no effect.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 471-477"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90088-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18901043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caffeine and ryanodine differentially modify a calcium-dependent component of soma action potentials in identified molluscan (Lymnaea stagnalis) neurones In situ","authors":"I.A. Ahmed ,&nbsp;P.M. Hopkins ,&nbsp;W. Winlow","doi":"10.1016/0742-8413(93)90072-S","DOIUrl":"10.1016/0742-8413(93)90072-S","url":null,"abstract":"<div><p>1. The main objectives of the present study were to investigate the effects of either caffeine or ryanodine on action potential shape in four identified neurones of <em>Lymnaea stagnalis</em> (L) <em>in situ</em>.</p><p>2. The action potential width at half-amplitude (half-width, HW) is a Ca²⁺ -dependent phenomenon and hence it was used here as a measure of spike broadening or narrowing. Spike data were analysed using a computer programme and appropriate statistical tests were performed.</p><p>3. Intracellular recordings were made under control conditions to establish the frequency/HW relationship for each cell type. Recordings were also made from each cell after perfusion with two concentrations of each drug and their effects on the frequency/HW relationship were studied.</p><p>4. Caffeine produced a significant increase in HW in three out of four studied neurones, whilst ryanodine produced a significant response in only one neurone and inconsistent results in the remainder. Therefore, both drugs were found to produce cell specific responses.</p><p>5. The data presented here are consistent with previous studies which demonstrate that both caffeine and ryanodine act as mobilizing agents for intracellular calcium from internal storage sites, although by different mechanisms.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 363-372"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90072-S","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54006267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of catecholamines in turbellarians of Lake Baikal","authors":"Krister Eriksson ,&nbsp;Maria Reuter ,&nbsp;Oleg Timoshkin","doi":"10.1016/0742-8413(93)90093-Z","DOIUrl":"10.1016/0742-8413(93)90093-Z","url":null,"abstract":"<div><p>1. The catecholamine content in six endemic turbellarians of Lake Baikal was examined with high pressure liquid chromatography (HPLC).</p><p>2. The planarians <em>Archicotylus</em> sp., <em>Baikalobia</em> sp., <em>Bdellocephala angarensis, Rimacephalus arecepta, Sorocelis nigrofasciata</em> and the lecithoepitheliat <em>Geocentrophora wagini</em> were analysed.</p><p>3. Dopa and dopamine (DA) were detected in all species and noradrenaline was detected in all species except <em>Archicotylus</em>. DA dominates in all species.</p><p>4. Neither adrenaline nor the DA-metabolite DOPAC were detected.</p></div>","PeriodicalId":72650,"journal":{"name":"Comparative biochemistry and physiology. C: Comparative pharmacology","volume":"105 3","pages":"Pages 509-511"},"PeriodicalIF":0.0,"publicationDate":"1993-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0742-8413(93)90093-Z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54006544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}