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J Exp Biol (2020) 223 (17): jeb227736.
Published: 11 September 2020
...-conserving mechanisms that support diving are underdeveloped at birth in pinnipeds and cetaceans. This Review explores how underdeveloped physiology makes immature marine mammals vulnerable to disturbance. Acidosis Blood Bradycardia Cetacean Dive response Heart rate Hypercarbia Hypoxia...
J Exp Biol (2019) 222 (19): jeb208637.
Published: 2 October 2019
...Siri L. Elmegaard; Birgitte I. McDonald; Peter T. Madsen ABSTRACT Pronounced dive responses through peripheral vasoconstriction and bradycardia enable prolonged apnoea in marine mammals. For most vertebrates, the dive response is initiated upon face immersion, but little is known about the physical...
Includes: Supplementary data
Jeppe Kaczmarek, Colleen Reichmuth, Birgitte I. McDonald, Jakob H. Kristensen, Josefin Larson, Fredrik Johansson, Jenna L. Sullivan, Peter T. Madsen
J Exp Biol (2018) 221 (13): jeb176545.
Published: 9 July 2018
... of these factors on diving heart rate are poorly understood because of the difficulty of parsing their relative contributions in diving pinnipeds. Here, we examined the effects of apnea and external sensory inputs as autonomic drivers of bradycardia. Specifically, we hypothesized that (1) water stimulation...
J Exp Biol (2018) 221 (12): jeb182972.
Published: 22 June 2018
..., this cannot be done without a certain degree of bradycardia to compensate for the ensuing increase in peripheral vascular resistance, and that is what is observed in most voluntary dives (e.g. Kooyman and Campbell, 1972 ; Hill et al., 1987 ). Thus, without knowing how the animal is managing its muscle...
J Exp Biol (2018) 221 (1): jeb168740.
Published: 9 January 2018
... of bradycardia would be influenced by dive duration and activity, i.e. the dive f H response would be exercise modulated. In all dives, f H decreased compared with surface rates by at least 50% (mean maximum surface f H =173 beats min −1 , mean minimum dive f H =50 beats min −1 ); however, dive f H...
Includes: Supplementary data
J Exp Biol (2017) 220 (19): 3556–3564.
Published: 1 October 2017
... depression at elevated temperatures. Here, we investigated how water temperature (both acute and chronic exposures) affected the physiology of juvenile estuarine crocodiles ( Crocodylus porosus ) performing predator avoidance dives (i.e. fright-dives). Diving oxygen consumption, ‘fright’ bradycardia...
Includes: Supplementary data
J Exp Biol (2017) 220 (3): 445–454.
Published: 1 February 2017
...–contraction coupling genes were studied in fish acclimatised to normoxia in summer (+18°C) or winter (+2°C), and in winter fish after 1, 3 and 6 weeks of anoxia. Anoxia induced a sustained bradycardia from a heart rate of 10.3±0.77 beats min −1 to 4.1±0.29 beats min −1 ( P <0.05) after 5 weeks, and heart...
Erik Sandblom, Andreas Ekström, Jeroen Brijs, L. Fredrik Sundström, Fredrik Jutfelt, Timothy D. Clark, Anders Adill, Teija Aho, Albin Gräns
J Exp Biol (2016) 219 (18): 2880–2887.
Published: 15 September 2016
...% in reference fish) and reduced intrinsic cardiac pacemaker rate. A barostatic response was evident in both groups, as pharmacologically induced increases and decreases in blood pressure resulted in atropine-sensitive bradycardia and tachycardia, respectively. Yet, the tachycardia in Biotest fish...
J Exp Biol (2012) 215 (16): 2735–2741.
Published: 15 August 2012
...Shawn R. Noren; Traci Kendall; Veronica Cuccurullo; Terrie M. Williams SUMMARY A hallmark of the dive response, bradycardia, promotes the conservation of onboard oxygen stores and enables marine mammals to submerge for prolonged periods. A paradox exists when marine mammals are foraging underwater...
J Exp Biol (2005) 208 (5): 821–829.
Published: 1 March 2005
... by prazosin treatment (62.6±2.3), but increased significantly after a subsequent injection with atropine (69.1±2.1)( Fig. 2A ). In control fish post-branchial occlusion caused significant bradycardia (53.0±3.1). Conversely, pre-branchial occlusion caused a significant tachycardia(69.1±1.7). Prazosin treatment...
J Exp Biol (2004) 207 (25): 4451–4461.
Published: 1 December 2004
... ). Atropine was able to inhibit the branchial vascular responses to ACh but not the hypoxic bradycardia, suggesting the presence of muscarinic receptors on the heart and gill vasculature, and that the hypoxia induced bradycardia is of non-cholinergic origin. The results suggest that adenosine mediates...
J Exp Biol (2004) 207 (22): 3891–3898.
Published: 15 October 2004
... bradycardia sleep ontogeny cardiorespiratory control harbour seal Phoca vitulina As first hypothesized by Castellini( 1995 ), the rate of cardiorespiratory control development was quicker in the harbour seal,compared to elephant and Weddell seals. Although similar changes in cardiorespiratory...
J Exp Biol (2003) 206 (5): 867–876.
Published: 1 March 2003
.... Injection (0.1-0.3 mm deep) in different rostrocaudal, medial-lateral positions induced a bradycardia, either increased or decreased blood pressure, ventilation frequency and amplitude and, sometimes, an initial apnea. Often these responses occurred simultaneously in various different combinations...
J Exp Biol (2002) 205 (23): 3757–3765.
Published: 1 December 2002
...Nicole M. Elliott; Russel D. Andrews; David R. Jones SUMMARY While diving, harbour seals ( Phoca vitulina ) manage their oxygen stores through cardiovascular adjustments, including bradycardia, a concurrent reduction in cardiac output, and peripheral vasoconstriction. At the surface,post-dive...
J Exp Biol (2002) 205 (21): 3357–3365.
Published: 1 November 2002
.... This was accomplished by measuring cardiorespiratory variables during acute hypercarbia (20 min at P CO 2 =8 mmHg; 1 mmHg=0.133 kPa) in fish subjected to selective bilateral extirpation of the first gill arch. The cardiovascular responses to hypercarbia in the intact fish included a significant bradycardia (from 75.0...