Effects of the non-selective 5-HT receptor agonist, 5-carboxamidotryptamine, on plasma glucose levels in rats.
The effects of the 5-HT1A/1B/1D/5/7 receptor agonist, 5-carboxamidotryptamine (5-CT), on blood glucose, insulin and glucagon levels in rats were investigated. 5-CT above the dosage of 0.05 mg/kg elicited significant hyperglycemic effects and 0.1 mg/kg, induced a 35% increase in plasma glucose levels. 5-CT did not affect plasma glucagon, and serum insulin levels increased following the high dose of 5-CT. Adrenodemedullation abolished the 5-CT-induced hyperglycemia. Hyperglycemia induced by 5-CT was prevented by pretreatment with the 5-HT1/2/7 receptor antagonist, metergoline, and the 5-HT1/2/5/7 receptor antagonist, methysergide, although the 5-HT2A receptor antagonist, ketanserin, the 5-HT2A/2B/2C receptor antagonist, ritanserin, and the 5-HT3/4 receptor antagonist, tropisetron, had no effect. Although 5-CT has a high affinity with 5-HT1A receptors, the 5-HT1A and 5-HT1B and beta receptor antagonist, (-)-popranolol, did not affect 5-CT-induced hyperglycemia. These results indicate that 5-CT-induced hyperglycemia is elicited by facilitation of adrenaline release from the adrenal gland and that 5-CT-induced hyperglycemia is mediated by the 5-HT7 receptor unrelated to 5-HT1A, 5-HT1B, 5-HT2, 5-HT3, 5-HT4 or 5-HT5 receptors.
Yamada
J
J
Department of Pharmacology, Kobe Pharmaceutical University, Japan.
Sugimoto
Y
Y
Noma
T
T
Yoshikawa
T
T
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects*; D005934:Glucagon / Q000378:metabolism; D006943:Hyperglycemia / Q000139:chemically induced / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D008297:Male; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology
D001786:Blood Glucose; D007328:Insulin; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D014665:Vasodilator Agents; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D005934:Glucagon; C047087:5-carboxamidotryptamine; D011433:Propranolol