5-HT3 receptor binding sites are on capsaicin-sensitive fibres in the rat spinal cord.
Specific binding sites for [3H]zacopride were found in the dorsal part of the rat spinal cord, particularly in the superficial layers of the dorsal horn. These binding sites had the same pharmacological profile as 5-HT3 receptors in membranes from the rat entorhinal cortex or from NG 108-15 neuroblastoma-glioma cells. Administration of capsaicin (50 mg/kg s.c.) to neonatal rats to induce degeneration of unmyelinated primary sensory fibres resulted in a significant decrease in [3H]zacopride specific binding (-50%) in the dorsal zone of the spinal cord of 4 month-old rats. This decrease was as pronounced as the decrease in [3H]bremazocine and [3H]naloxone binding to opiate receptors. These data support the presynaptic location of 5-HT3 receptors, at least in part, on capsaicin-sensitive primary afferent fibres in the rat spinal cord.
INSERM U.288, Neurobiologie Cellulaire et Fonctionnelle, Faculté de Médecine Pitié-Salpêtrière, Paris, France.
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Gallissot
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D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D000932:Antiemetics / Q000378:metabolism; D001345:Autoradiography; D001549:Benzamides / Q000378:metabolism; D001575:Benzomorphans / Q000378:metabolism; D001643:Bridged Bicyclo Compounds / Q000378:metabolism; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002211:Capsaicin / Q000494:pharmacology*; D008297:Male; D009270:Naloxone / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D000932:Antiemetics; D001549:Benzamides; D001575:Benzomorphans; D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D009419:Nerve Tissue Proteins; D011985:Receptors, Serotonin; D009270:Naloxone; C055971:zacopride; C027248:bremazocine; D002211:Capsaicin