Effects of adrenoceptor antagonists and neuronal uptake inhibitors on dimethylphenylpiperazinium-induced release of catecholamines from the rabbit isolated adrenal gland and guinea-pig atria

Journal Article · Thu Nov 01 04:00:00 EST 1984 · J. Pharmacol. Exp. Ther.; (United States)

OSTI ID:6005719

Collett, A R; Story, D F

Isolated rabbit adrenal glands were perfused with Krebs-Henseleit solution at 37 degrees C and the catecholamine storage sites were labeled with (/sup 3/H)epinephrine. Release of radioactivity was evoked by 2-min periods of perfusion with dimethylphenylpiperazinium (DMPP, 100 microM). DMPP-induced efflux of radioactivity was decreased by desipramine (1 microM), cocaine (30 microM), phenoxybenzamine (1 and 10 microM), phentolamine (1, 3 and 10 microM) and propranolol (1 microM). The reduction in DMPP-induced efflux cannot be accounted for by interactions with alpha adrenoceptors, as prazosin (1 microM) and yohimbine (1 microM) were without effect. There also was no correlation between inhibition of DMPP-induced efflux and ability of the drugs to inhibit catecholamine uptake as phentolamine (1 microM) and propranolol (1 microM) did not affect the incorporation of (/sup 3/H)epinephrine by the gland. In guinea-pig atria, in which the catecholamine storage sites had been labeled with (/sup 3/H)norepinephrine, efflux of radioactivity was elicited by 1-min periods of contact with DMPP. DMPP-induced efflux of radioactivity from atria was decreased by desipramine (1 microM), cocaine (30 microM), phenoxybenzamine (1 and 10 microM), phentolamine (1 and 10 microM) and propranolol (1 microM) but not by prazosin (1 microM) or yohimbine (1 microM). The inhibition of DMPP-induced efflux in guinea-pig atria could not be correlated with alpha adrenoceptor antagonism or blockade of neuronal uptake. There were differences between the two preparations in the degree of inhibition of DMPP-induced release produced by the above drugs.

• Research Organization: Univ. of Melbourne, Victoria, Australia
• OSTI ID: 6005719
• Journal Information: J. Pharmacol. Exp. Ther.; (United States), Journal Name: J. Pharmacol. Exp. Ther.; (United States) Vol. 231:2; ISSN JPETA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL GLANDS
ADRENAL HORMONES
ADRENALINE
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOCHEMICAL REACTION KINETICS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATECHOLAMINES
DRUGS
ENDOCRINE GLANDS
GLANDS
GUINEA PIGS
HORMONES
HYDROXY COMPOUNDS
IN VITRO
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PERFUSED ORGANS
PHENOLS
POLYPHENOLS
RABBITS
REACTION KINETICS
RODENTS
STEROID HORMONES
SYMPATHOLYTICS
SYMPATHOMIMETICS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES