| Abstract: | The hypothermia inducing action of clonidine and guanfacine was abolished by yohimbine and idazoxan pretreatment which suggests an alpha 2-adrenoceptor involvement in this effect. The effects of acute and chronic treatment with the antidepressant drugs desipramine (DMI), amitriptyline (AMI), maprotiline (MAP), mianserin (MIAN), iprindol (IPR), alaproclate (ALA) and electroconvulsive treatment (ECT) on the hypothermic action of the alpha 2-adrenoceptor agonists clonidine and guanfacine were studied. Acute administration of MIAN potentiated clonidine induced hypothermia whereas acute MIAN, IPR and ALA potentiated guanfacine induced hypothermia. Repetitive DMI, AMI and MAP treatment attenuated clonidine-induced hypothermia whereas guanfacine-induced hypothermia was potentiated by chronic treatment with DMI, AMI, MAP and MIAN, ECT applied without anaesthesia attenuated both clonidine and guanfacine hypothermia, however, under ethyl ether anaesthesia ECT was effective only towards guanfacine hypothermia. This discrepancy is discussed in terms of the relative selectivity of the agonists used, the reliability of agonist studies for indexing receptor function, and possible pharmacokinetic interaction. |
