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Activation of melanocortin receptors accelerates the gonadotropin-releasing hormone pulse generator activity in goats.
- Source :
-
Neuroscience letters [Neurosci Lett] 2005 Aug 05; Vol. 383 (3), pp. 289-94. - Publication Year :
- 2005
-
Abstract
- The present study aims to elucidate whether the central melanocortin receptors [melanocortin-3 and -4 receptors (MC3/4-R)] are involved in regulating GnRH pulse generator activity in female goats. The GnRH pulse generator activity was electrophysiologically assessed at the intervals of characteristic increases in multiple-unit activity (MUA volleys) in the mediobasal hypothalamus. In ovariectomized goats, all doses (0.02, 0.2 and 2 nmol) of MT II, an MC3/4-R agonist, injected into the lateral ventricle significantly shortened MUA volley intervals. The duration of the period during which MT II accelerated MUA volleys was positively correlated with the dose of MT II injected. The stimulatory effect of MT II on the GnRH pulse generator activity was attenuated in the presence of estrogen. Intracerebroventricular injection of SHU9119, an MC3/4-R antagonist, significantly prolonged MUA volley intervals at 1 nmol. MT II (0.2 nmol)-induced acceleration of MUA volleys was partially blocked by the antagonism of MC3/4-R with pre-administered SHU9119 (1 nmol). The present findings demonstrate that MC3/4-R are involved in maintaining GnRH pulse generator activity in goats.
- Subjects :
- Action Potentials drug effects
Animals
Dose-Response Relationship, Drug
Drug Interactions
Electrophysiology methods
Estradiol pharmacology
Estrogen Antagonists pharmacology
Female
Goats
Gonadotropin-Releasing Hormone antagonists & inhibitors
Hypothalamus, Middle drug effects
Injections, Intraventricular methods
Melanocyte-Stimulating Hormones pharmacology
Oligopeptides pharmacology
Ovariectomy methods
Receptors, Melanocortin antagonists & inhibitors
Time Factors
Action Potentials physiology
Gonadotropin-Releasing Hormone metabolism
Hypothalamus, Middle physiology
Receptors, Melanocortin metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0304-3940
- Volume :
- 383
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Neuroscience letters
- Publication Type :
- Academic Journal
- Accession number :
- 15955423
- Full Text :
- https://doi.org/10.1016/j.neulet.2005.04.026