The role of the 5-HT1a receptor in central cardiovascular regulation

The aim of the studies describe~ in this thesis is to further clarify the role of the 5- HT1A receptor in central cardiovascular regulation. The hypotensive action of 5-HT1A receptor agonists is mainly due to differential sympatho-inhibition resulting in an increase in total peripheral vascular conductance (Wouters et al, 1988b). The first part of the thesis deals with the effects of activating the 5-HT1A receptor with the selective 5- HT1A receptor agonists 8-0H-f>PAT and .flesinoxan on the haemodynamic profile of anaesthetized cats and conscious rats. This part of the thesis will provide better insight into which vascular beds are responsible for the increase in total peripheral conductance as caused by 5-HT1A receptor activation. In the second part, a study will be presented comparing the cardiovascular effects of the 5-HT1A receptor agonists 8-0H-DPAT and flesinoxan in several rat models. Also. the results of a pharmacological study will be shown in order to provide evidence that the cardiovascular effects of 8-0H-DPAT and flesinoxan are indeed mediated by 5-HT1A receptors. The last part of the thesis will deal with the central sites. possibly involved in mediating the cardiovascular effects of 5-HTrA receptor agonists. In this part the effects of central administration of 5-HT1A receptor agonists on cardiovascular control will be discussed