D-2 dopamine receptor activation reduces free ( sup 3 H)arachidonate release induced by hypophysiotropic peptides in anterior pituitary cells
- Univ. of Catania School of Medicine (Italy)
Dopamine reduces the stimulation of intracellular ({sup 3}H)arachidonate release produced by the two PRL-stimulating peptides angiotensin-II and TRH. This effect is concentration dependent and is mediated by stimulation of D-2 dopamine receptors. D-2 receptor agonists (bromocriptine, dihydroergocryptine, and dihydroergocristine) inhibit the release of fatty acid induced by angiotensin-II with a potency that parallels their ability to inhibit PRL release in vitro. Conversely, the selective D-2 receptor antagonist L-sulpiride completely prevents dopamine's effect, whereas SCH 23390 (a D-1 receptor antagonist) is ineffective. The inhibitory action of dopamine does not seem to be consequent to an action on the adenylate cyclase-cAMP system, as 8-bromo-cAMP (1 mM) does not affect either basal or dopamine-inhibited ({sup 3}H)arachidonate release. However, a 24-h pertussis toxin pretreatment significantly reduces the action of dopamine on fatty acid release. Collectively, these results suggest that D-2 dopamine receptor-mediated inhibition of intracellular ({sup 3}H)arachidonate release requires the action of a GTP-binding protein, but is not a consequence of an inhibitory action on cAMP levels.
- OSTI ID:
- 5547367
- Journal Information:
- Endocrinology; (USA), Journal Name: Endocrinology; (USA) Vol. 125:3; ISSN ENDOA; ISSN 0013-7227
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMINES
ANGIOTENSIN
ANIMALS
ANTIGENS
ARACHIDONIC ACID
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOCHEMICAL REACTION KINETICS
BODY
CARBOXYLIC ACIDS
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CULTURES
DOPAMINE
DRUGS
ENDOCRINE GLANDS
GLANDS
GLOBULINS
GONADOTROPINS
HORMONES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INHIBITION
ISOTOPE APPLICATIONS
KINETICS
LTH
MAMMALS
MATERIALS
MEMBRANE PROTEINS
MONOCARBOXYLIC ACIDS
NEUROREGULATORS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PEPTIDES
PHENOLS
PITUITARY GLAND
PITUITARY HORMONES
POLYPHENOLS
PROTEINS
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SECRETION
SYMPATHOLYTICS
SYMPATHOMIMETICS
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VASOCONSTRICTORS
VERTEBRATES