Antagonism by chlorisondamine and propranolol, but not by atenolol, of the circadian phase-dependent phentolamine-induced changes in the cardiac noradrenaline turnover in the rat
- 1 September 1980
- journal article
- research article
- Published by Springer Nature in Naunyn-Schmiedebergs Archiv für experimentelle Pathologie und Pharmakologie
- Vol. 313 (3), 205-212
- https://doi.org/10.1007/bf00505735
Abstract
The effects of phentolamine alone or in combination with propranolol, atenolol and chlorisondamine were studied on the concentration and turnover of noradrenaline in the heart of light-dark (L:D=12:12h) synchronized rats. In order to detect possible circadian phase-dependent variations in the drug effects, the same experiments were performed in the light-period and dark-period, respectively. The parameters of the turnover were calculated from the exponential decline of i.v. injected 3H-(-)-noradrenaline. Phentolamine significantly decreased the noradrenaline concentration during L, but not during D. Reduction in 3H-noradrenaline accumulation by phentolamine was 42.3% during L and 22.2% during D. Phentolamine increased the turnover rate of cardiac noradrenaline more than 3-fold in either photoperiod. Chlorisondamine reversed all the effects of phentolamine studied. Propranolol, but not atenolol, antagonized the effects of phentolamine in a dose-dependent and stereospecific way, being more effective when applied during D. Thus, the chronopharmacological studies in unrestrained rats show a circadian phase-dependency of the effects of adrenoceptor blocking drugs. It is concluded that a central site of action is responsible for the antagonism by propranolol of the phentolamine-induced increase in the turnover of the cardiac noradrenaline in vivo.Keywords
This publication has 20 references indexed in Scilit:
- Diurnal rhythms in noradrenaline turnover and motility after reserpine and 6-hydroxydopaminePharmacology Biochemistry and Behavior, 1979
- The Central Uptake of β-Adrenoceptor AntagonistsJournal of Pharmacy and Pharmacology, 1977
- Reduction in sympathetic nervous activity as a mechanism for hypotensive effect of propranololNature, 1975
- Pharmacological studies of two new cardioselective adrenergic beta-receptor antagonistsLife Sciences, 1973
- Antagonism by propranolol of the inhibitory effect of phenoxybenzamine on noradrenaline uptake in vivoJournal of Pharmacy and Pharmacology, 1971
- The influence of drug treatment on norepinephrine levels and ultrastructure of the rat hypothalamus and caudate nucleus during a programmed light-dark cycleNeuropharmacology, 1971
- Autoradiographic Distribution Studies of Adrenergic Blocking Agents. II. 14C‐Propranolol, a β‐Receptor‐Type BlockerActa Pharmacologica et Toxicologica, 1967
- Central nervous system effects of four β-adrenergic receptor blocking agentsJournal of Pharmacy and Pharmacology, 1966
- A sensitive method for spectrophotofluorometric assay of catecholaminesInternational Journal of Neuropharmacology, 1964
- A Multiple Comparison Procedure for Comparing Several Treatments with a ControlJournal of the American Statistical Association, 1955