Prevention by morphine of apomorphine- and oxytocin-induced penile erection and yawning: site of action in the brain.
The effect of morphine administered systemically or into the paraventricular nucleus of the hypothalamus (PVN) on penile erection and yawning induced either by oxytocin or by the dopaminergic agonist apomorphine was studied in male rats. Systemic morphine (0.5 to 5 mg/kg intraperitoneally [IP]) prevented in a dose-dependent manner penile erection and yawning induced by the intracerebroventricular injection (ICV) of oxytocin (30 ng) or by the subcutaneous (SC) administration of apomorphine (80 micrograms/kg). Morphine (0.1 to 5 micrograms), but not U-69,593 (5 micrograms), injected into the PVN 10 minutes before oxytocin or apomorphine, was found to be able to prevent penile erection and yawning induced by the unilateral PVN microinjection of oxytocin (10 ng) or apomorphine (50 ng). The morphine-induced prevention of these behavioral responses was abolished by pretreatment with naloxone (3 mg/kg IP) 15 minutes before morphine. The present results suggest that morphine prevents apomorphine- and oxytocin-induced penile erection and yawning by inhibiting the activity of oxytocinergic neurons through mu-type receptors in this hypothalamic nucleus.[1]References
- Prevention by morphine of apomorphine- and oxytocin-induced penile erection and yawning: site of action in the brain. Melis, M.R., Stancampiano, R., Gessa, G.L., Argiolas, A. Neuropsychopharmacology (1992) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg