RIZATRIPTAN HAS CENTRAL ANTINOCICEPTIVE EFFECTS AGAINST DURALLY EVOKED-RESPONSES

The 5-HT1B/1D receptor agonist rizatriptan constricts intracranial, ex tracerebral blood vessels, inhibits neurogenic vasodilation and extrav asation in the meninges and is effective clinically against migraine. The present study has investigated whether rizatriptan may also have a ctivity at 5-HT1B/1D receptors within the central nervous system (CNS) that contributes to its antimigraine effects. Action potentials evoke d by electrical stimulation of the dura-mater were recorded extracellu larly from single neurones in the trigeminal nucleus caudalis in anaes thetized rats. Rizatriptan dose dependently inhibited these nociceptiv e dural responses by up to 63 +/- 9% after 3 mg/kg, i.v. Rizatriptan t herefore has central activity which may contribute to its efficacy aga inst migraine headache.