Antibodies against SP receptors from rat olfactory bulb (Ant-Rc- olf) and intestinal mucosa (Ant-Rc-Int) prepared by immunizing New Zealand white rabbits with the purified receptors were proved active in binding to fixed tissue sections and the isolated receptor proteins by immunocytochemical localization and western blot respectively. A project on screening SP clones from rat hypothalamus cDNA library has been initiated in April 1988 in collaboration with Genentech, Inc. Project on amino acid sequence of SP receptor protein has been carried out in collaboration with Dr. B. Martin. The results will be obtained as soon as the problem of transferring the purified protein from the acrylamide gel to the immobilin (polyvinylidene difluoride, PDrF) membrane is resolved. Reports of the evidence that SP, the putative neurotransmitter, is distributed in the midbrain periaquedactal gray (PAG), suggest the possibility of SP involvement in the pain processing mechanism in PAG. Therefore the localization of substance P (SP) and SP binding sites were conducted on the periaqueductal gray (PAG) of the rat to examine their correlationship. Autoradiograms and immunocytochemical localization revealed an uneven distribution of both specific binding sites and SP-immunoreactivity (SP-ir) respectively.
