1 the effect of isoprenaline on diastolic blood pressure and heart rate was determined in anaesthetized male rats which had been housed individually for 6-8 weeks after weaning , and compared with its effect in group-housed litter-mate controls.2 isoprenaline caused a significantly greater fall in diastolic pressure in isolated rats and a greater increase in heart rate.3 low doses of noradrenaline ( 5-10 ng ) caused vasodepressor responses in isolated , but not in group-housed rats.4 the pressor response to noradrenaline , which was smaller in isolated rats , was increased to the level of group-housed controls by ( +/- ) -propranolol.5 prolonged isolation of rats may bring about an increase in sensitivity of beta-adrenoceptors to isoprenaline and noradrenaline .
C0428977
heart rate
C0033497
propranolol