| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Indiana University School of Medicine, South Bend Center for Medical Education, University of Notre Dame, Notre Dame, Indiana 46556
The
significance of the sympathetic nervous system (SNS) in regulating
peripheral vascular resistance and cardiac function in fish has been
well established, whereas its effect on venous function in vivo is
unknown. Two protocols were employed in the present study to evaluate
SNS effects on the venous system in intact, unanesthetized trout. In
the first, trout were instrumented with pressure cannulas in the
ventral (PVA) and dorsal
(PDA) aortas and ductus Cuvier
(PVEN), and cardiac output (CO)
was measured with a flow probe around the ventral aorta. Heart rate,
stroke volume, and gill and systemic resistances were calculated from the measured parameters. In the second group, vascular capacitance curves were obtained by monitoring mean circulatory filling pressure (PVEN) during transient
interruption of CO and while blood volume was adjusted between 80 and
120% of normal. Unstressed blood volume (USBV) and vascular compliance
(C) were derived from the capacitance curves. Infusion of epinephrine
(Epi; 3.3 nmol · min
1 · kg
body wt1) increased
PVA,
PDA, and
PVEN, whereas norepinephrine (NE)
infusion (3.3 nmol · min1 · kg
body wt1) increased
PVA and
PDA but did not affect
PVEN. Epi (1.0 nmol · min1 · kg
body wt1), but not NE
(2.6 or 10.4 nmol · min1 · kg
body wt1), displaced the
capacitance curve to the right and significantly decreased USBV.
Inhibition of 
1-adrenoceptors
with prazosin, or ganglionic nicotinic receptor blockade with
hexamethonium, produced a left shift in the capacitance curve, and
both treatments increased USBV and C. Conversely, the
-adrenoceptor antagonist phentolamine did not effect
vascular capacitance. These results show that Epi has potent effects on
trout veins in vivo and that it mobilizes blood from the unstressed
into the stressed vascular compartment and augments central venous
pressure by decreasing venous compliance. These results also show that
the SNS is an active effector of venous tone and compliance in trout;
this is the first demonstration of tonic regulation of vascular
capacitance in any fish.
vascular capacitance; venous compliance; unstressed volume; sympathetic nervous system; cardiovascular control
This article has been cited by other articles:
|
|
 |
|
  K. R. Olson and T. M. Hoagland Effects of freshwater and saltwater adaptation and dietary salt on fluid compartments, blood pressure, and venous capacitance in trout Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R1061 - R1067. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Sandblom and M. Axelsson Venous hemodynamic responses to acute temperature increase in the rainbow trout (Oncorhynchus mykiss) Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2007; 292(6): R2292 - R2298. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Sandblom, M. Axelsson, and A. P. Farrell Central venous pressure and mean circulatory filling pressure in the dogfish Squalus acanthias: adrenergic control and role of the pericardium Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2006; 291(5): R1465 - R1473. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Mitzner, J. V. Tyberg, M. K. Stickland, V. J. B. Robinson, L. B. Rowell, E. Sandblom, M. Axelsson, A. P. Farrell, and A. A. Shoukas The following letters are in response to the Point:Counterpoint series "Hypoxic pulmonary vasoconstriction is/is not mediated by increased production of reactive oxygen species" that appears in this issue. J Appl Physiol, October 1, 2006; 101(4): 1267 - 1268. [Full Text] [PDF]
|
|
|
|
|
|
E. Sandblom and M. Axelsson Adrenergic control of venous capacitance during moderate hypoxia in the rainbow trout (Oncorhynchus mykiss): role of neural and circulating catecholamines Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2006; 291(3): R711 - R718. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Altimiras and M. Axelsson Intrinsic autoregulation of cardiac output in rainbow trout (Oncorhynchus mykiss) at different heart rates J. Exp. Biol., January 15, 2004; 207(2): 195 - 201. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. R. Minerick, H.-C. Chang, T. M. Hoagland, and K. R. Olson Dynamic synchronization analysis of venous pressure-driven cardiac output in rainbow trout Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2003; 285(4): R889 - R896. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. M. Hoagland, L. Weaver Jr., J. M. Conlon, Y. Wang, and K. R. Olson Effects of endothelin-1 and homologous trout endothelin on cardiovascular function in rainbow trout Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2000; 278(2): R460 - R468. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
