1. Noradrenaline, adrenaline and alpha-methylnoradrenaline administration into the nucleus tractus solitarii (NTS) of anaesthetized rats decreased blood pressure and heart rate in a dose-dependent fashion. 2. Bilateral injections were effective in lower doses than unilateral administration. alpha-Methylnoradrenaline given bilaterally produced hypotension in a dose of 0-08 nmol whereas after uni...