Temporal effects of intrahypothalamic 5,7-dihydroxytryptamine: relationship between serotonin levels and [3H]serotonin binding.
The relationship between serotonin (5-HT) levels and [3H]5-HT binding in discrete hypothalamic areas was examined in separate groups of animals at various times, following unilateral intrahypothalamic injection of 5,7-dihydroxytryptamine (5,7-DHT). Seven days post-5,7-DHT lesion, 5-HT levels were significantly decreased in both the ipsilateral and contralateral ventromedial and dorsomedial hypothalamic nuclei (VMN, DMN). In the lateral hypothalamic area (LHA), 5-HT levels were significantly decreased only ipsilaterally. Fifty days postlesion, 5-HT levels in the ipsilateral VMN remained significantly below sham, while the DMN and LHA returned to sham values. Seven days after 5,7-DHT there was a significant increase in [3H]5-HT labeling densities in the ipsilateral and contralateral ventromedial hypothalamic area as well as in the ipsilateral LHA. In contrast, in the dorsomedial hypothalamic area there was no increase in [3H]5-HT binding. Fifty days postlesion, no significant differences in [3H]5-HT binding between 5,7-DHT and sham were observed in any areas examined. This data provides further evidence for the regeneration of 5-HT fibers in the hypothalamus and demonstrates that the relationship between [3H]5-HT binding and 5-HT levels varies from one hypothalamic area to another.
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology*; D000818:Animals; D004102:Dihydroxytryptamines / Q000494:pharmacology*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*; D013997:Time Factors
D004102:Dihydroxytryptamines; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid