Evidence for the presence of PNMT-containing cell bodies in the hypothalamus.
The presence of intrinsic neurons in the hypothalamus containing the enzyme phenylethanolamine N-methyltransferase (PNMT), was investigated by selective destruction of the local cell bodies with kainic acid (KA), a potent excitotoxin. The unilateral stereotaxic injection of 2 micrograms of KA into the lateral hypothalamus produced a 30-35% decrease in the hypothalamic PNMT activity in the lesioned side compared with the contralateral uninjected side. The difference was statistically significant for up to 4 days after the lesion. The unilateral lesion did not have a unilateral effect on epinephrine or norepinephrine content as there was a significant reduction on both sides (50% for epinephrine and 30% for norepinephrine compared with saline injected). These data suggest the presence of intrinsic cell bodies in the lateral hypothalamus, containing the epinephrine-forming enzyme but lacking epinephrine storage sites. Our results support the previous hypothesis of the dissociation between epinephrine present in the hypothalamus and hypothalamic PNMT activity.
Masana
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MI
Section on Clinical Pharmacology, National Institute of Mental Health, Bethesda, MD 20892.
Mefford
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IN
D000818:Animals; D007026:Hypothalamic Area, Lateral / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D010625:Phenylethanolamine N-Methyltransferase; D007608:Kainic Acid