Cardiovascular changes in the rainbow trout (Salmo gairdneri Richardson) during exercise

1982 ◽  
Vol 60 (5) ◽  
pp. 1135-1140 ◽  
Author(s):  
D. J. Randall ◽  
C. Daxboeck

The effects of steady-state, aerobic swimming exercise upon the cardiovascular system of rainbow trout (Salmo gairdneri) are discussed. When these fish are forced to swim at 80% of their critical velocity, blood flow is redistributed in the systemic circulation to favour working muscles, at the expense of decreased flow to nonmuscle structures. Given oxygen uptake and cardiac output data, combined with blood flow distribution patterns during exercise, it is calculated that the working muscles can account for nearly all the measured increase in total oxygen uptake at this level of exercise. The possible underlying mechanisms for systemic blood flow control and the increase in gas exchange efficiency across the gills of exercising rainbow trout also are examined.

1983 ◽  
Vol 105 (1) ◽  
pp. 1-14
Author(s):  
PETER NEUMANN ◽  
GEORGE F. HOLETON ◽  
NORBERT HEISLER

Rainbow trout (Salmo gairdneri) were electrically stimulated to exhausting activity and the changes in cardiac output and blood flow distribution to gills and systemic tissues resulting from the developing severe lactacidosis were repeatedly measured by the microsphere method (15 μm). Determination of cardiac output by application of the Fick principle resulted in values not significantly different from cardiac output measured by the indicator dilution technique, suggesting that cutaneous respiration, oxygen consumption, and arterio-venous shunting were insignificant under these conditions. Following muscular activity, cardiac output was elevated by up to 60%. In the gills, the blood flow distribution in the gill arches showed a consistent pattern, even during lactacidosis, with a higher perfusion in gill arches II and III, and in the middle sections of individual gills. Blood flow to white and red muscle was increased much more than cardiac output (+230 and +490%, respectively) such that blood flow to other tissues was actually reduced. We conclude that the elimination of lactate from muscle cells during the recovery period from strenuous exercise is delayed, not as a result of an impaired post-exercise muscle blood flow, but probably as a result of a high diffusion resistance in the cell membrane. Note: Deceased.


1982 ◽  
Vol 243 (2) ◽  
pp. H296-H306 ◽  
Author(s):  
M. H. Laughlin ◽  
R. B. Armstrong

Muscle blood flow (BF) was measured using the radiolabeled microsphere technique within and among nine major muscles of rats before exercise and during treadmill walking or running at speeds of 15, 30, 45, 60, and 75 m/min. Measurements were made during exercise after 1 min of steady walking or running. Male Sprague-Dawley rats were chronically instrumented with 2 Silastic catheters, one in the ascending aorta via the right carotid artery for microsphere infusion and one in the left renal artery for arterial reference blood sample withdrawal. The preexercise results demonstrated that 1) BF to deep slow-twitch muscles was three to four times that to peripheral fast muscles (e.g., soleus and gastrocnemius BFs were 138 and 33 ml . min-1 . 100 g-1, respectively); 2) BFs to red portions within mixed muscles were three to four times those to white portions (e.g, red and white gastrocnemius BFs were 54 and 18 ml . min-1 . 100 g-1, respectively; and 3) there was a direct relationship (P less than 0.05) between BFs to muscles and their slow-twitch oxidative fiber populations. The results obtained during exercise demonstrated that 1) at the slowest speed studied (15 m/min) BFs to the red portions of muscles increased, whereas BFs to the white portions of the same muscles decreased; 2) BFs to all muscles (except soleus) were increased during running at 75 m/min when there was a range of flows of 30 ml . 100 g-1 . min-1 (white gastrocnemius) to 321 (vastus intermedius), 3) at all running speeds the increases in BF to muscles were directly related to the fast-twitch, high-oxidative fiber populations of the muscles; and 4) BFs to visceral tissues and fat were decreased during exercise.


2013 ◽  
Vol 33 (12) ◽  
pp. 1915-1920 ◽  
Author(s):  
Shigehiko Ogoh ◽  
Kohei Sato ◽  
Kazunobu Okazaki ◽  
Tadayoshi Miyamoto ◽  
Ai Hirasawa ◽  
...  

The purpose of the present study was to assess the effect of heat stress-induced changes in systemic circulation on intra- and extracranial blood flows and its distribution. Twelve healthy subjects with a mean age of 22±2 (s.d.) years dressed in a tube-lined suit and rested in a supine position. Cardiac output (Q), internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA) blood flows were measured by ultrasonography before and during whole body heating. Esophageal temperature increased from 37.0±0.2°C to 38.4±0.2°C during whole body heating. Despite an increase in Q (59±31%, P<0.001), ICA and VA decreased to 83±15% ( P=0.001) and 87±8% ( P=0.002), respectively, whereas ECA blood flow gradually increased from 188±72 to 422±189 mL/minute (+135%, P<0.001). These findings indicate that heat stress modified the effect of Q on blood flows at each artery; the increased Q due to heat stress was redistributed to extracranial vascular beds.


1971 ◽  
Vol 28 (10) ◽  
pp. 1609-1614 ◽  
Author(s):  
John C. Davis

Reductions in surface area of the gill were artificially produced by ligating various gill arches and occluding their blood supply. Rainbow trout (Salmo gairdneri) responded to a 40–57% reduction in gill area, by increasing cardiac output and ventilation volume, and probably by redistributing blood within the remaining functional gill area. Fish with blood flow to gill arches one and three only, could maintain arterial PO2 at 90–100 mm Hg, whereas, in those with blood flow to arches three and four only, arterial PO2 fell to around 40 mm Hg. The presence of a chemoreceptor site for the regulation of arterial PO2 associated with the efferent blood vessels of arch number one is discussed. Such a receptor may be located in the pseudobranch or in the portion of the brain supplied with arterial blood from the first gill arch.


1982 ◽  
Vol 243 (1) ◽  
pp. G1-G9 ◽  
Author(s):  
P. R. Kvietys ◽  
D. N. Granger

Many vasoactive agents are known to alter oxygen uptake by splanchnic organs. Data from the literature indicate that, in general, vasodilators increase, whereas vasoconstrictors decrease oxygen uptake. We compare and contrast the effects of vasoactive agents on oxygen uptake observed in vivo, under constant-flow and free-flow conditions, to those observed in vitro. The discrepancies between the in vivo and in vitro data are discussed relative to the effects of vasoactive agents on blood flow, intraorgan blood flow distribution, the countercurrent exchange of oxygen, capillary exchange capacity, and oxidative metabolism. Changes in blood flow, oxidative metabolism, and capillary density appear to be the major mechanisms by which vasoactive agents alter splanchnic oxygen uptake in vivo. Experimental designs are proposed that may help minimize inconsistencies in the data in future studies.


Physiology ◽  
1989 ◽  
Vol 4 (6) ◽  
pp. 219-225 ◽  
Author(s):  
AWJ Cowley ◽  
C Hinojosa-Laborde ◽  
BJ Barber ◽  
DR Harder ◽  
JH Lombard ◽  
...  

The contribution of local autoregulatory mechanisms to the overall control of the systemic circulation has been analyzed using theoretical and experimental approaches. Mechanisms that regulate regional vascular resistance and contribute importantly to the overall moment-to-moment regulation of cardiac output and total peripheral resistance are reviewed.


Sign in / Sign up

Export Citation Format

Share Document