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Sympathetic nervous system mediation of acute cardiovascular actions of gamma 2-melanocyte-stimulating hormone.
- Source :
-
Hypertension (Dallas, Tex. : 1979) [Hypertension] 1985 May-Jun; Vol. 7 (3 Pt 2), pp. I145-50. - Publication Year :
- 1985
-
Abstract
- Peptides of the pro-opiocortin class produce pronounced cardiovascular and natriuretic actions. We have investigated the acute cardiovascular effects of one of the most potent members of this class, gamma 2-melanocyte stimulating hormone (gamma 2-MSH), in rats. Pressor actions of gamma 2-MSH administered systemically were eliminated by ganglionic blockade with chlorisondamine. Peripheral cholinergic blockade failed to affect either the pressor or cardioaccelerator responses to gamma 2-MSH. Administration of gamma 2-MSH (2.0-10.0 micrograms) produced vasoconstriction primarily in the mesenteric and hindlimb vascular beds, while the renal bed showed little response. Infusions of phenylephrine produced pressor responses similar to those found with gamma 2-MSH, which were accompanied by a decrease in heart rate and vasoconstriction in the mesenteric and renal vascular beds. Hemodynamic changes produced by gamma 2-MSH and phenylephrine were blocked or attenuated by alpha 1-adrenergic receptor blockade with prazosin. Direct injection of gamma 2-MSH into the renal artery produced an acute renal vasoconstriction that was not attenuated by alpha 1-adrenergic or ganglionic blockade. These findings and the results of previous publications are consistent with the hypothesis that gamma 2-MSH may produce a centrally mediated activation of the sympathetic nervous system, have direct vasoconstriction actions on the renal vasculature, and inhibit baroreceptor function to produce an increase in blood pressure without an accompanying bradycardia.
- Subjects :
- Adrenergic alpha-Antagonists pharmacology
Animals
Blood Pressure drug effects
Ganglionic Blockers pharmacology
Male
Natriuresis drug effects
Phenylephrine pharmacology
Prazosin pharmacology
Pressoreceptors metabolism
Rats
Rats, Inbred Strains
Vascular Resistance drug effects
Cardiovascular System drug effects
Hemodynamics drug effects
Melanocyte-Stimulating Hormones pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0194-911X
- Volume :
- 7
- Issue :
- 3 Pt 2
- Database :
- MEDLINE
- Journal :
- Hypertension (Dallas, Tex. : 1979)
- Publication Type :
- Academic Journal
- Accession number :
- 2860063
- Full Text :
- https://doi.org/10.1161/01.hyp.7.3_pt_2.i145