caa a22 4500 605514038 CHVBK 20210128100703.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s00360-015-0910-z doi (NATIONALLICENCE)springer-10.1007/s00360-015-0910-z Autonomic control of post-air-breathing tachycardia in Clarias gariepinus (Teleostei: Clariidae) [Elektronische Daten] [Mariana Teixeira, Vinicius Armelin, Augusto Abe, Francisco Rantin, Luiz Florindo] The African catfish (Clarias gariepinus) is a teleost with bimodal respiration that utilizes a paired suprabranchial chamber located in the gill cavity as an air-breathing organ. Like all air-breathing fishes studied to date, the African catfish exhibits pronounced changes in heart rate (f H) that are associated with air-breathing events. We acquired f H, gill-breathing frequency (f G) and air-breathing frequency (f AB) in situations that require or do not require air breathing (during normoxia and hypoxia), and we assessed the autonomic control of post-air-breathing tachycardia using an infusion of the β-adrenergic antagonist propranolol and the muscarinic cholinergic antagonist atropine. During normoxia, C. gariepinus presented low f AB (1.85±0.73 ABh−1) and a constant f G (43.16±1.74 breathsmin−1). During non-critical hypoxia (PO2=60mmHg), f AB in the African catfish increased to 5.42±1.19 ABh−1 and f G decreased to 39.12±1.58 breathsmin−1. During critical hypoxia (PO2=20mmHg), f AB increased to 7.4±1.39 ABh−1 and f G decreased to 34.97±1.78 breathsmin−1. These results were expected for a facultative air breather. Each air breath (AB) was followed by a brief but significant tachycardia, which in the critical hypoxia trials, reached a maximum of 143% of the pre-AB f H values of untreated animals. Pharmacological blockade allowed the calculation of cardiac autonomic tones, which showed that post-AB tachycardia is predominantly regulated by the parasympathetic subdivision of the autonomic nervous system. Springer-Verlag Berlin Heidelberg, 2015 African catfish nationallicence Autonomic control nationallicence Air breathing nationallicence Hypoxia nationallicence Tachycardia nationallicence Teixeira Mariana Department of Zoology and Botany, São Paulo State University (UNESP), Cristóvão Colombo Street, 2265, 15054-000, São José Do Rio Preto, SP, Brazil aut Armelin Vinicius Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luiz, km 235, 13565-905, São Carlos, SP, Brazil aut Abe Augusto Department of Zoology, São Paulo State University (UNESP), 24A Avenue, 1515, 13506-900, Rio Claro, SP, Brazil aut Rantin Francisco Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luiz, km 235, 13565-905, São Carlos, SP, Brazil aut Florindo Luiz Department of Zoology and Botany, São Paulo State University (UNESP), Cristóvão Colombo Street, 2265, 15054-000, São José Do Rio Preto, SP, Brazil aut Journal of Comparative Physiology B Springer Berlin Heidelberg 185/6(2015-08-01), 669-676 0174-1578 185:6<669 2015 185 360 https://doi.org/10.1007/s00360-015-0910-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00360-015-0910-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Teixeira Mariana Department of Zoology and Botany, São Paulo State University (UNESP), Cristóvão Colombo Street, 2265, 15054-000, São José Do Rio Preto, SP, Brazil aut NATIONALLICENCE 700 1- Armelin Vinicius Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luiz, km 235, 13565-905, São Carlos, SP, Brazil aut NATIONALLICENCE 700 1- Abe Augusto Department of Zoology, São Paulo State University (UNESP), 24A Avenue, 1515, 13506-900, Rio Claro, SP, Brazil aut NATIONALLICENCE 700 1- Rantin Francisco Department of Physiological Sciences, Federal University of São Carlos (UFSCar), Via Washington Luiz, km 235, 13565-905, São Carlos, SP, Brazil aut NATIONALLICENCE 700 1- Florindo Luiz Department of Zoology and Botany, São Paulo State University (UNESP), Cristóvão Colombo Street, 2265, 15054-000, São José Do Rio Preto, SP, Brazil aut NATIONALLICENCE 773 0- Journal of Comparative Physiology B Springer Berlin Heidelberg 185/6(2015-08-01), 669-676 0174-1578 185:6<669 2015 185 360