title: [Effect of chronic oral administration of clonidine on the endogenous catecholamine metabolism in spontaneously hypertensive rats (author's transl)].
abstract: The present experiments were undertaken to elucidate the effect of chronic oral administration of clonidine on the endogenous catecholamine metabolism in spontaneously hypertensive rats (SHR). A three month administration of clonidine (20 microgram/kg/day p.o.) produced a slight decrease in blood pressure and heart rate. No significant change was observed in the body weight. A one month administration of clonidine (300 microgram/kg/day p.o.) produced hypotension and weight loss. No significant effect was observed in heart rate. After a two month administration of clonidine (300 microgram/kg/day p.o.), the catecholamine content in the brainstem showed a significant decrease as compared with that in control. 3H-norepinephrine (NE) turnover rate after intraventr culari injection of 3H-NE tended to decrease in the brainstem of SHR while no significant difference was recognized from a view point of uptake, biological half life, elimination rate constant of 3H-NE between control and clonidine administered rats. Under the same experimental conditions, a marked rebound hypertension occurred when medication is discontinued in some cases of this group of SHR.
mesh_terms: D000284:Administration, Oral; D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D001933:Brain Stem / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism*; D003000:Clonidine / Q000008:administration & dosage* / Q000494:pharmacology; D004435:Eating / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D013375:Substance Withdrawal Syndrome
chemical_list: D002395:Catecholamines; D003000:Clonidine; D009638:Norepinephrine