[Neuropharmacologic analysis and clinical course of ketamine anesthesia during central alpha2-adrenostimulation with...

The experiments on white male rats have established that clopheline preinjection shortens the latent period and prolongs the duration of ketamine anesthesia due to alpha 2-, alpha 2- and beta 2-adrenoceptor mechanisms, respectively. An additional administration of prazosin and naloxone (0.1 mg/kg) potentiates the duration of combined clopheline and ketamine anesthesia. The duration of ketamine anesthesia alone remains unchanged in simultaneous alpha 1- and alpha 2-adrenoceptor blockade with phentolamine, however, it is prolonged in alpha 1-adrenoceptor blockade and shortened in alpha 2-adrenoceptor blockade with prazosin and yohimbine, respectively. Tachycardiac effects of ketamine are removed with clopheline due to alpha 2-adrenostimulation and beta 1-adrenoblockade with talinolol or attenuated upon reserpine administration. The combined use of clopheline and ketamine for the termination of pregnancy, as compared to combined diazepam and ketamine anesthesia, prolongs the duration of anesthesia, normalizes basic hemodynamic parameters prior to and following the injection of an anesthetic and promotes to a more adequate discontinuation of anesthesia.