WHAT INTRACRANIAL TISSUES IN HUMANS CONTAIN SUMATRIPTAN-SENSITIVE SEROTONIN 5-HT1-TYPE RECEPTORS

We investigated the presence of sumatriptan-sensitive serotonin (5-HT) (1) receptors in different human tissues by using a radioligand-bindin g technique with [H-3]5-HT. Sumatriptan displaced [H-3]5-HT from front al cortical and striatal membranes in a biphasic manner, with a high-a ffinity site corresponding to binding to the 5-HT1D receptor. In blood platelet membranes, sumatriptan displaced [H-3]S-HT with a 100-fold l ower affinity. Sumatriptan failed to displace [H-3]5-HT in membranes f rom large cerebral arteries, pial vessels, coronary arteries and dura mater. These findings suggest that either there are no sumatriptan-sen sitive 5-HT1 receptors on intracranial blood vessels or they are so sm all in number that they cannot be detected by the radioligand-binding technique. Other mechanisms, possibly centrally mediated, may be respo nsible for the antimigraine action of sumatriptan.