EXPRESSION OF SUBSTANCE-P RECEPTOR IN THE SUBSTANTIA-NIGRA

Since the substantia nigra receives abundant substance P innervations but lacks clear evidences about a presence of substance P receptors, e xpressions for mRNA and protein of substance P receptors were investig ated in the rat to resolve this mismatch. Expression levels of substan ce P receptors mRNA in the substantia nigra pars compacta and reticula ta were 37.7 and 24.1% of those in the striatum, respectively, by reve rse transcription-polymerase chain reaction (RT-PCR). Substance P rece ptors mRNA was found in dopamine neurons of the substantia nigra pars compacta by single cell RT-PCR. Ca. 90% of dopamine neurons in the sub stantia nigra pars compacta were immunoreactive to anti-substance P re ceptor antibody in the colchicine treated rats. These are the first di rect evidence for the existence of substance P receptors in dopamine n eurons of the substantia nigra pars compacta. (C) 1998 Elsevier Scienc e B.V.