Pharmacological differences between the D-2 autoreceptor and the D-1 dopamine receptor in rabbit retina

Journal Article · Sat Jun 01 04:00:00 EDT 1985 · J. Pharmacol. Exp. Ther.; (United States)

OSTI ID:5253864

Dubocovich, M L; Weiner, N

The effect of dopamine receptor agonists and antagonists was studied on the calcium-dependent release of (/sup 3/H)dopamine elicited by field stimulation at 3 Hz for a duration of 1 min (20 mA, 2 msec) from the rabbit retina in vitro and on adenylate cyclase activity in homogenates of rabbit retina. The relative order of potency of dopamine receptor agonists to inhibit the stimulation-evoked (/sup 3/H)dopamine release was pergolide greater than bromocriptine greater than apomorphine greater than LY 141865 greater than N,N-di-n-propyldopamine greater than or equal to dopamine. The relative order of potencies of dopamine receptor antagonists to increase (/sup 3/H)dopamine release was: S-sulpiride greater than or equal to domperidone greater than or equal to spiroperidol greater than metoclopramide greater than fluphenazine greater than or equal to R-sulpiride. alpha-Flupenthixol (0.01-1 microM) and (+)-butaclamol (0.01-1 microM) did not increase (/sup 3/H)dopamine overflow when added alone, but they antagonized the concentration-dependent inhibitory effect of apomorphine (0.1-10 microM). These results suggest that the dopamine inhibitory autoreceptor involved in the modulation of dopamine release from the rabbit retina possesses the pharmacological characteristics of a D-2 dopamine receptor. Maximal stimulation by 30 microM dopamine resulted in a 3-fold increase in adenylate cyclase activity with half-maximal stimulation occurring at a concentration of 2.46 microM. Apomorphine and pergolide elicited a partial stimulation of adenylate cyclase activity. However, at low concentrations both compounds were more potent than dopamine.

• Research Organization: Univ. of Colorado School of Medicine, Denver
• OSTI ID: 5253864
• Journal Information: J. Pharmacol. Exp. Ther.; (United States), Journal Name: J. Pharmacol. Exp. Ther.; (United States) Vol. 3; ISSN JPETA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METALS
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
BODY AREAS
CALCIUM
CARDIOTONICS
CARDIOVASCULAR AGENTS
COMPARATIVE EVALUATIONS
CYCLASES
DOPAMINE
DRUGS
ELEMENTS
ENZYME ACTIVITY
ENZYMES
EYES
FACE
HEAD
HOMOGENATES
HYDROXY COMPOUNDS
IN VITRO
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LYASES
MAMMALS
METALS
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PHENOLS
POLYPHENOLS
RABBITS
RECEPTORS
RETINA
SENSE ORGANS
SYMPATHOMIMETICS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES