...Ayaka Saito; Chihiro Kinoshita; Kino Sakai; Katsufumi Sato; Kentaro Q. Sakamoto ABSTRACT Air-breathing vertebrates exhibit cardiovascular responses to diving including heart rate reduction (diving bradycardia). Field studies on aquatic mammals and birds have shown that the intensity of bradycardia...

...Ayaka Saito; Chihiro Kinoshita; Megumi Kawai; Takuya Fukuoka; Katsufumi Sato; Kentaro Q. Sakamoto ABSTRACT Diving bradycardia is a reduction in the heart rate mediated by the parasympathetic system during diving. Although diving bradycardia is pronounced in aquatic mammals and birds, the existence...

... to activation of the sympathetic system and also to a reduction in parasympathetic tone. Heart rate decreased markedly during voluntary submergence in controls but rose as muskrats swam submerged against increasing water flows. Nevertheless, diving bradycardia was still present. Free-diving bradycardia...

...Pierre E. Signore; David R. Jones ABSTRACT Neural control of free and forced diving bradycardia and peripheral resistance was studied in the muskrat ( Ondatra zibethicus ) by means of acute pharmacological blockade with the muscarinic blocker atropine, the α -adrenergic blocker phentolamine...

.... The onset of pronounced bradycardia was delayed with each successive trial, until little or no bradycardia occurred during submergence. Diving bradycardia is driven by chemoreceptors in the dabbler and caused by stimulation of narial receptors in the diver. Mean arterial blood pressure in dives...