title: Chronic beta-adrenergic stimulation increases in mice the sensitivity to methysergide and the number of cerebral high affinity serotonin binding sites (5-HT-1).
abstract: Reserpine administration in mice causes, among other effects an akinesia which can be reversed by the serotonin agonist-antagonist methysergide. The effect of methysergide is potentiated by clenbuterol, a beta-adrenergic agonist, which itself causes hypomotility. Potentiation is weak after a single injection of clenbuterol, but becomes much stronger after repeated administration for 12 days. This treatment also causes a 50% increase in the number of high affinity 5-HT-1 binding sites in the brain. This increase would explain the increased potency of methysergide against reserpine-induced akinesia. These results show that: a beta-adrenergic drug, clenbuterol modulates the serotoninergic system; this modulation takes its importance after chronic treatment only; this interrelation may be important in depressive illness since it is observed on a test used in the screening of antidepressant drugs.
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002976:Clenbuterol / Q000008:administration & dosage*; D004357:Drug Synergism; D004983:Ethanolamines / Q000008:administration & dosage*; D008297:Male; D008784:Methysergide / Q000008:administration & dosage*; D051379:Mice; D009069:Movement Disorders / Q000139:chemically induced; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D012110:Reserpine / Q000037:antagonists & inhibitors; D012701:Serotonin / Q000378:metabolism*
chemical_list: D004983:Ethanolamines; D011943:Receptors, Adrenergic, beta; D012701:Serotonin; D012110:Reserpine; D002976:Clenbuterol; D008784:Methysergide