AIMS This study dealt with the effect of chronic ethanol administration on hemodynamic responses elicited by alpha(2)-adrenergic (alpha-methyldopa) or I(1)-imidazoline (rilmenidine) receptor activation in telemetered female rats. MAIN METHODS The effects of alpha-methyldopa or rilmenidine on blood pressure (BP), heart rate (HR) and their variability were investigated in rats that received liq...

To determine whether or not alpha-methyladrenaline (MA) is an active metabolite of alpha-methyldopa, a centrally-acting hypotensive compound, we measured MA in the rat brain using the high-performance liquid chromatographic electrochemical detection method. After five daily treatments of alpha-methyldopa given twice daily a dose of 40 mg/kg, we found trace amounts of MA in the hypothalamus and ...

This symposium reviewed the fundamental principles, pharmacology, and clinical pharmacology of central alpha-adrenergic blood pressure regulating mechanisms. Fundamental principles Arterial baro- and chemoreceptor signals reach the nucleus of the tractus solitarius (NTS) via vagal and glossopharyngeal afferents. The NTS communicates with sympathetic preganglionic neurons in the spinal cord via ...

Hypertension often coexists with hyperlipidemia, insulin resistance, and glucose intolerance, a comorbidity known as metabolic syndrome X. Different antihypertensives have mixed effects on these associated abnormalities. We compared three antihypertensives in the spontaneously hypertensive obese rat model of syndrome X. Moxonidine (4 mg/kg), an imidazoline and alpha2-adrenergic agonist, alpha-m...

Intracisternal (i.c.) and intravenous (i.v.) administration of methyldopa in conscious rabbits produced closely similar changes in hemodynamics, heart rate, and falls in plasma norepinephrine levels. Two weeks after giving i.c. 6-hydroxydopamine (6-OHDA), when there is widespread destruction of central noradrenergic neurons, the effects of i.c. methyldopa virtually were abolished. This suggests...

The effects of D-methamphetamine HCl (1, 2 and 4 mg/kg, i.p.) and alpha-methyldopa (1, 2 and 4 mg/kg, i.p.) on rectal temperature and on ethanol (3 g/kg, i.p.)-induced hypothermia have been investigated in mice. Methamphetamine caused a dose-dependent hyperthermia, but methyldopa induced hypothermia, which decreased with increases in dose. Methamphetamine antagonized the hypothermic effect of e...