Decreased uptake of 3H-serotonin and endogenous content of serotonin in blood platelets in hypertensive patients
The uptake and content of serotonin in blood platelets were studied in patients with essential hypertension and in five families in which at least one member was hypertensive. Blood was obtained from male and female normotensive volunteers and hypertensive patients who were free of medication. Lineweaver-Burk plots of 3H-serotonin uptake from both control subjects and hypertensive patients were linear, which suggested simple Michaelis-Menten uptake kinetics. The maximal uptake velocity (Vmax) in hypertensive patients was significantly lower than in control subjects (control . 41.7 +/- 3.3 pmol/min/10(8) platelets, n . 17; hypertensive . 26.6 +/- 3.0 pmol/min/10(8) platelets, n . 16; p less than 0.005). The affinity constant (Km) was slightly but significantly lower in hypertensive patients (control . 0.70 +/- 0.08 microM; hypertensive . 0.46 +/- 0.08 microM; p less than 0.05). The serotonin content in blood platelets determined by high pressure liquid chromatography with electrochemical detection was significantly lower in hypertensive patients (control . 165.0 +/- 12.9 nmol/10(11) platelets, n . 29; hypertensive . 105.9 +/- 10.4 nmol/10(11) platelets, n . 27; p less than 0.001). In the five families investigated, the lowered serotonin content was observed in some normotensive members. The reduced number of carriers of serotonin uptake and the slight decrease in the affinity constant observed in platelets of patients with essential hypertension suggest that serotonin metabolism is altered in essential hypertension and that blood platelets may be a useful model in studying the serotonergic modifications at the molecular level.
- Research Organization:
- Department of Pharmacology, U7 INSERM, Hopital Necker, Paris, France
- OSTI ID:
- 6549773
- Journal Information:
- Hypertension (Dallas); (United States), Journal Name: Hypertension (Dallas); (United States) Vol. 6:4; ISSN HPRTD
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AMINES
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
AZAARENES
AZOLES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD CHEMISTRY
BLOOD PLATELETS
BODY FLUIDS
CARDIOVASCULAR DISEASES
DISEASES
DRUGS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
HYPERTENSION
INDOLES
KINETICS
LABELLED COMPOUNDS
MATERIALS
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PATHOGENESIS
PATIENTS
PYRROLES
RADIOPROTECTIVE SUBSTANCES
REACTION KINETICS
SEROTONIN
SYMPATHOMIMETICS
SYMPTOMS
TRITIUM COMPOUNDS
TRYPTAMINES
UPTAKE
VASCULAR DISEASES