Kaycee N Moyer, João Brandão, Hugues Beaufrère, Andrea Sanchez, Julianne E McCready
{"title":"Atropine and glycopyrrolate significantly raise the heart rate of Sonoran Desert toads (Incilius alvarius).","authors":"Kaycee N Moyer, João Brandão, Hugues Beaufrère, Andrea Sanchez, Julianne E McCready","doi":"10.2460/ajvr.26.05.0215","DOIUrl":null,"url":null,"abstract":"<p><strong>Objective: </strong>To evaluate the effects of atropine and glycopyrrolate on the heart rate (HR) of Sonoran Desert toads (Incilius alvarius).</p><p><strong>Methods: </strong>In part 1, toads received 0.1 mg/kg atropine IM, 0.025 mg/kg glycopyrrolate IM, 0.05 mg/kg glycopyrrolate IM, saline, or negative control in a randomized crossover study. Heart rate was monitored at baseline and 1, 3, 5, 10, 15, 20, 25, 30, 40, 50, and 60 minutes. In part 2, toads received 10 mg/kg alfaxalone IM followed by 0.05 mg/kg glycopyrrolate or saline. Heart rate was monitored at baseline and 1, 3, 5, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100, and 120 minutes.</p><p><strong>Results: </strong>In part 1 (n = 19), all 3 anticholinergic protocols significantly increased the HR between 3 and 15 minutes versus both controls. Atropine significantly increased the HR versus saline between 3 and 30 minutes. Both glycopyrrolate doses significantly increased the HR versus saline at 60 minutes. In part 2 (n = 10), glycopyrrolate significantly increased the HR versus saline at 10 minutes (mean HR difference 6.8 beats/min, SE of the difference 1.467 [95% CI, 1.024 to 12.58]).</p><p><strong>Conclusions: </strong>Atropine and glycopyrrolate significantly increased the HR in conscious toads, with glycopyrrolate having longer efficacy. The effective period of glycopyrrolate was briefer in alfaxalone-sedated toads.</p><p><strong>Clinical relevance: </strong>Performing safe, effective anesthesia can be challenging in amphibians given their unique physiology. Anticholinergic drugs are commonly used in veterinary medicine to address anesthesia-induced bradycardia. Additional studies are indicated to further evaluate the clinical efficacy of anticholinergics in amphibians.</p>","PeriodicalId":7754,"journal":{"name":"American journal of veterinary research","volume":" ","pages":""},"PeriodicalIF":1.6000,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"American journal of veterinary research","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.2460/ajvr.26.05.0215","RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2026/10/1 0:00:00","PubModel":"Print","JCR":"Q2","JCRName":"VETERINARY SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Objective: To evaluate the effects of atropine and glycopyrrolate on the heart rate (HR) of Sonoran Desert toads (Incilius alvarius).
Methods: In part 1, toads received 0.1 mg/kg atropine IM, 0.025 mg/kg glycopyrrolate IM, 0.05 mg/kg glycopyrrolate IM, saline, or negative control in a randomized crossover study. Heart rate was monitored at baseline and 1, 3, 5, 10, 15, 20, 25, 30, 40, 50, and 60 minutes. In part 2, toads received 10 mg/kg alfaxalone IM followed by 0.05 mg/kg glycopyrrolate or saline. Heart rate was monitored at baseline and 1, 3, 5, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100, and 120 minutes.
Results: In part 1 (n = 19), all 3 anticholinergic protocols significantly increased the HR between 3 and 15 minutes versus both controls. Atropine significantly increased the HR versus saline between 3 and 30 minutes. Both glycopyrrolate doses significantly increased the HR versus saline at 60 minutes. In part 2 (n = 10), glycopyrrolate significantly increased the HR versus saline at 10 minutes (mean HR difference 6.8 beats/min, SE of the difference 1.467 [95% CI, 1.024 to 12.58]).
Conclusions: Atropine and glycopyrrolate significantly increased the HR in conscious toads, with glycopyrrolate having longer efficacy. The effective period of glycopyrrolate was briefer in alfaxalone-sedated toads.
Clinical relevance: Performing safe, effective anesthesia can be challenging in amphibians given their unique physiology. Anticholinergic drugs are commonly used in veterinary medicine to address anesthesia-induced bradycardia. Additional studies are indicated to further evaluate the clinical efficacy of anticholinergics in amphibians.
期刊介绍：
The American Journal of Veterinary Research supports the collaborative exchange of information between researchers and clinicians by publishing novel research findings that bridge the gulf between basic research and clinical practice or that help to translate laboratory research and preclinical studies to the development of clinical trials and clinical practice. The journal welcomes submission of high-quality original studies and review articles in a wide range of scientific fields, including anatomy, anesthesiology, animal welfare, behavior, epidemiology, genetics, heredity, infectious disease, molecular biology, oncology, pharmacology, pathogenic mechanisms, physiology, surgery, theriogenology, toxicology, and vaccinology. Species of interest include production animals, companion animals, equids, exotic animals, birds, reptiles, and wild and marine animals. Reports of laboratory animal studies and studies involving the use of animals as experimental models of human diseases are considered only when the study results are of demonstrable benefit to the species used in the research or to another species of veterinary interest. Other fields of interest or animals species are not necessarily excluded from consideration, but such reports must focus on novel research findings. Submitted papers must make an original and substantial contribution to the veterinary medicine knowledge base; preliminary studies are not appropriate.
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