Evidence for hypothalamic noradrenergic involvement in naloxone-induced stimulation of luteinizing hormone release.
A single injection of the opiate antagonist, naloxone (NAL), resulted in a fourfold increase in serum luteinizing hormone (LH) concentration 20 min after injection. To determine whether noradrenergic neurons were involved, male Sprague-Dawley rats were treated with alpha-methyl-p-tyrosine (alpha-MPT), phenoxybenzamine hydrochloride (PBH), or diethyldithiocarbamate (DDC), all anti-noradrenergic drugs. Reduction of hypothalamic norepinephrine synthesis by alpha-MPT or DDC, or blockade of the alpha-receptors by PBH, resulted in complete suppression of NAL-induced LH release. These results suggest that the NAL-induced increase in LH release is mediated in part via a hypothalamic noradrenergic mechanism.
D000818:Animals; D007031:Hypothalamus / Q000502:physiology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology*; D009638:Norepinephrine / Q000502:physiology*; D010643:Phenoxybenzamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D019805:alpha-Methyltyrosine
D008781:Methyltyrosines; D010643:Phenoxybenzamine; D009270:Naloxone; D019805:alpha-Methyltyrosine; D007986:Luteinizing Hormone; D009638:Norepinephrine