Labetalol infusion is becoming more commonly used in controlling the blood pressure during anaesthesia in different situation. This work was designed to study the controlled hypotensive effect of labetalol infusion with any possible effect on the skeletal muscle. It was found that labeta lol infusion (100 ug/kg minute) produced a gradual reduction of the sys tolic blood pressure jroml 10 8 to 70 6 mm Hg and the diastollc blood pressure from 100 8 to 60 6 mm Hg. This hypotensive effect w'as mentained during the infusion of labetalol. After stoppage of infusion the blood pressure and the H. R returned within 20 mtn. to their normal lev els. Also, it was observed that labetalol infusion attenuated the vasopressor effects of phenylepherine (1 ug/kg), adrenaline (1 ug/kg) and abo lished completely the hypotensive effect of isoprenaline (0.5 ug/kg). Moreover, during labetalol infusion, there was 20 % reduction in the con traction of gasterocnemius of cats. This reduction was not reversed by stoppage of infusion but it was reversed by I. V. infusion of neosttgmtne (100 ug/kg). In addition, it was observed that the relaxant effect ofDTC |
