Melatonin has been shown to act on certain vascular beds. However, the identity of melatonin receptors in the cerebral artery has not been established. In the present study, we have attempted to identify melatonin receptor mRNAs of rat cerebral artery by using a reverse transcriptase polymerase chain reaction technique. Total RNAs were extracted from the cerebral artery and different regions of male Sprague-Dawley rats. Amplification of RNAs from pineal gland, hypothalamus and cerebral artery with mt(1) while amplification of RNAs from pineal gland and hypothalamus with mt(2) primers resulted in products of the predicted lengths. The result indicated that mt(1) but not mt(2) melatonin receptor was expressed in the rat cerebral artery, whereas abdominal aorta did not express any type of melatonin receptor. Further studies are necessary to understand the significance of this receptor in regulating physiological function.