title: 5-Hydroxytryptophan and carbidopa in spontaneously hypertensive rats.
abstract: Serial measurements of blood pressure, body weight, food and water intake, and salt and water excretion were compared in two groups of spontaneously hypertensive rats (SHR) over a 12-day period: control SHR (n = 11) and a group (n = 9) which received supplementary 5-hydroxytryptophan (5-HTP; 2 mg/ml) in its drinking water. During the final 4 days of study, both groups received additional oral carbidopa (50 mg/kg twice a day) to inhibit peripheral, but not brain aromatic L-amino-acid decarboxylase (LAAD), an enzyme necessary to the formation of 5-hydroxytryptamine (5-HT, serotonin) from 5-HTP. 5-Hydroxytryptophan increased urinary 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) markedly; following carbidopa, urinary 5-HT, and to a lesser degree urinary 5-HIAA, decreased, whereas brain 5-HT and 5-HIAA increased. Spontaneously hypertensive rats treated with 5-HTP plus carbidopa had significantly lower blood pressure levels, lower pulse rates, reductions in food and water intake, salt and water excretion, and a loss of body weight, when compared with the control SHR. These data indicate that enhanced brain formation of 5-HT can give rise to metabolic and circulatory responses with a resultant lowering of blood pressure.
authors: Department of Medicine, New York Medical College, Valhalla 10595.
authors: H D
authors: HD
authors: Itskovitz
authors: J L
authors: JL
authors: Werber
authors: A M
authors: AM
authors: Sheridan
authors: T F
authors: TF
authors: Brewer
authors: C T
authors: CT
authors: Stier
mesh_terms: D006916:5-Hydroxytryptophan / Q000627:therapeutic use*; D000818:Animals; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D001794:Blood Pressure; D001921:Brain / Q000378:metabolism; D002230:Carbidopa / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy* / Q000235:genetics; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D012701:Serotonin / Q000378:metabolism; D015431:Weight Loss
chemical_list: D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D012701:Serotonin; D006916:5-Hydroxytryptophan; D002230:Carbidopa