ISSN:
1432-1912
Keywords:
Contractile force
;
Dipyridamole
;
Dog
;
Noradrenaline
;
Papillary muscle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary In the arterially blood-perfused canine papillary muscle, i.a. injections of dipyridamole (10–300 μg) produced a dose-dependent increase in developed tension amounting to about 45% of the basal developed tension at 300 μg. The positive inotropic response to dipyridamole was greatly reduced by a prior i.a. injection of propranolol (10 μg) or by pretreatment with reserpine (0.2 mg/kg s.c. for 3 consecutive days) but not affected by a prior i.a. injection of tetrodotoxin (1 μg) or desmethylimipramine (3–10 μg). The positive inotropic response to dipyridamole reduced by pretreatment with reserpine was restored by i.a. infusion of noradrenaline (0.03 μg/min). Dipyridamole did not modify the positive inotropic responses to noradrenaline and tyramine. These results suggest that the positive inotropic response to dipyridamole is largely due to noradrenaline released from adrenergic nerve endings by a mechanism that differs from those operative in the action of tyramine or in liberation of noradrenaline upon excitation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00692782
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