...Benjamin J. van Soldt; Tobias Wang; Renato Filogonio; Carl Christian Danielsen ABSTRACT The walls of the mammalian aorta and pulmonary artery are characterized by diverging morphologies and mechanical properties, which have been correlated with high systemic and low pulmonary blood pressure...

... positive chronotropic effects. To investigate whether this tonic elevation of heart rate impairs the ability for autonomic regulation of heart during digestion, we characterised heart rate responses to pharmacological manipulation of blood pressure in the snake Boa constrictor through serial injections...

... response was identified in terms of a faster return of heart rate to baseline values during the recovery period of the 10th session of restraint. The increase in blood pressure and the decrease in tail skin temperature were similar at the 1st and 10th session of restraint. Exposure to CVS, social isolation...

... differences between splenectomized (unable to release erythrocytes from the spleen) and sham-operated individuals, we demonstrate the metabolic benefits (i.e. aerobic scope increase of 103%) and the cardiovascular trade-offs (i.e. ventral aortic blood pressure and cardiac workload increase of 12% and 30...

...% 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...

...Lucas A. Zena; Valter Dantonio; Luciane H. Gargaglioni; Denis V. Andrade; Augusto S. Abe; Kênia C. Bícego ABSTRACT Baroreflex regulation of blood pressure is important for maintaining appropriate tissue perfusion. Although temperature affects heart rate ( f H ) reflex regulation in some reptiles...

...Sanne Enok; Christopher Slay; Augusto S. Abe; James W. Hicks; Tobias Wang Interspecific allometric analyses indicate that mean arterial blood pressure (MAP) increases with body mass of snakes and mammals. In snakes, MAP increases in proportion to the increased distance between the heart...

..., the maximum hyperventilatory effect of PACAP was approximately 2.5-fold higher than the effect of VIP at the 100 pmol dose (PACAP, =+5407±921 arbitrary units, a.u.; VIP, =+2056±874 a.u.; means ± s.e.m.). When injected centrally, only PACAP produced a significant increase in mean dorsal aortic blood pressure...

... by coronary arteries. The functional importance of these coronary arteries remains unknown. In the present study we investigate the effects of permanent coronary artery occlusion in the South American rattlesnake ( Crotalus durissus ) on the ability to maintain heart rate and blood pressure at rest and during...

... (e-mail: nini.jensen@biology.au.dk ) 15 8 2005 © The Company of Biologists Limited 2005 2005 turtle Trachemys reptile blood flow blood pressure systemic circulation pulmonary circulation endothelin ET A -receptor ET B -receptor Vascular tone is regulated...

.... 4E ), but blood flow was maintained ( Fig. 4D )owing to the concomitant 19% increase in stroke volume. A small and transient increase in blood pressure also occurred( Fig. 4B ); this response was not observed in untreated fish. * Author for correspondence (e-mail: Katie.Gilmour...

..., we examine the branchial effects of severe hypoxia (<0.3 mg oxygen l –1 for 20 min in anaesthetized epaulette shark), by measuring ventral and dorsal aortic blood pressure ( P VA and P DA ), heart rate ( f h ), and observing gill microcirculation using epi-illumination microscopy. Hypoxia induced...

...Gina Galli; E. W. Taylor; Tobias Wang SUMMARY Seven freshwater turtles Trachemys scripta were instrumented with flow probes and cannulated for blood pressure measurements. The turtles were warmed from 24 to 34°C, and cooled down to 24°C, with and without atropine. Animals exhibited a hysteresis...

...J. A. W. Stecyk; J. Overgaard; A. P. Farrell; T. Wang SUMMARY Anoxic exposure in the anoxia-tolerant freshwater turtle is attended by substantial decreases in heart rate and blood flows, but systemic blood pressure ( P sys ) only decreases marginally due to an increase in systemic peripheral...

... are well separated by the muscular ridge, and a previous study using in situ perfusion of the heart revealed a remarkable flow separation and showed that the systemic side can sustain higher output pressures than the pulmonary side. Here we extend these observations by showing that systemic blood pressure...

... was then microinjected into identified sites within the Xs in an attempt to mimic chemoreceptor- and baroreceptor-induced reflexes commonly observed in fish. By necessity, the brain injections were performed on anaesthetised animals that were fixed by `eye bars' in a recirculating water system. Blood pressure and heart...

... these results, it is apparent that active control over the timing of valve closure allows pulmonary input resistance and thus shunting to be controlled somewhat independently of systemic blood pressure or chronic pulmonary resistance and allows the shunt to be initiated or terminated in, perhaps, a single heart...

... equipped with an arterial catheter for measurements of blood pressure and heart rate, and autonomic tonus was determined following infusion of the β-adrenergic antagonist propranolol (3 mg kg –1 ) and the muscarinic cholinoceptor antagonist atropine (3 mg kg –1 ). The mean heart rate of fasting animals...

...Lena Sundin; Michael Axelsson; William Davison; Malcolm E. Forster ABSTRACT We have investigated the effects of adenosine on the cardiovascular system of the Antarctic fish Pagothenia borchgrevinki . Continuous measurements of ventral and dorsal aortic blood pressures, heart rate ( f H) and ventral...

...). Experiments were performed to examine, for the first time, the influence of hypercapnic acidosis on aspects of cardiovascular physiology including blood pressure, cardiac output and vascular resistance. Fish displayed dose (water CO 2 partial pressure) -dependent increases in ventral aortic (13–39...