Neonatal 5,7-DHT lesions upregulate [3H]mesulergine-labelled spinal 5-HT1C binding sites in the rat.
To delineate the involvement of spinal 5-HT1C receptors in supersensitivity and recovery following neonatal 5,7-DHT lesions, we injected rats on postnatal days 2 and 5 with 5,7-DHT or vehicle by intraperitoneal (IP) or intracisternal (IC) injection. [3H]Mesulergine-labelled sites measured 4 or 14 weeks later exhibited a significant increase (+35% for IP and 27% for IC) in Bmax without changes in Kd or nH. Spinal 5-HT content was significantly reduced (-80 to 89%) by either route of 5,7-DHT injection. These data describe novel upregulation of spinal 5-HT1C receptors in rats with neonatal 5,7-DHT lesions. Spinal 5-HT1C receptor upregulation may contribute to the behavioral supersensitivity to L-5-hydroxytryptophan (L-5-HTP) in rats with 5,7-DHT lesions. It does not explain the behavioral recovery we found previously only after IP 5,7-DHT injection.
Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY.
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Pranzatelli
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D000978:Antiparkinson Agents / Q000494:pharmacology; D002946:Cisterna Magna; D004873:Ergolines; D005260:Female; D066298:In Vitro Techniques; D007267:Injections; D007274:Injections, Intraperitoneal; D007700:Kinetics; D008297:Male; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*; D015854:Up-Regulation
D000978:Antiparkinson Agents; D004873:Ergolines; D011985:Receptors, Serotonin; D015116:5,7-Dihydroxytryptamine; C031649:mesulergine