ISSN:
1432-136X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The effects of adrenaline on the development of force under anoxia and hypercapnic acidosis (13% CO2 in 30 mM HCO 3 − ) were examined in isolated, electrically stimulated cardiac ventricle strips of rainbow trout and eel. During anoxia or acidosis applied 15 min in advance, the adrenaline concentration of the bathing solution was increased in 5 steps from 0 to 10−4 M with 5 min at each step. Before levelling off the contractile tension increased by 145±42% (mean±SE) in the anoxic, 80±14% in the acidotic and 152±41% in the control trout cardiac strips. Except for the acidotic strips the corresponding values tended to be lower for the eel strips being 46±9%, 57±17% and 57±9%, respectively. The inotropic affinity for adrenaline was lower in the trout than in the eel myocardium. For the trout myocardium it remained unchanged, while it decreased somewhat for the eel myocardium under anoxia or acidosis. Adding to the muscle bath 10−5 M adrenaline resulted in an increase in force development by about 90% for the trout myocardium and 50% for the eel myocardium. 5 min later anoxia or hypercapnic acidosis was applied for 30 min followed by 30 min at control conditions. Relative to the force values recorded just before anoxia or acidosis was applied, the changes in contractile force during these periods were the same with and without adrenaline. Thus adrenaline appears to have a persistent positive inotropic effect in the fish myocardium during and after oxygen lack or acidosis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00689300
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