Localization of tachykinin receptors and Fos-like immunoreactivity induced by substance P in guinea-pig brain.
1. In the present study, a comparison was made between the distribution of tachykinin NK1 and NK3 receptor immunoreactivity and the distribution of Fos-like immunoreactivity induced by the tachykinin agonist substance P (SP) in the guinea-pig brain. 2. In agreement with results from previous studies in rat brain, NK1 receptor-immunoreactive neurons were found to be widely distributed throughout the brain in the striatum and in diencephalic and mesencephalic structures, while NK3 receptor-immunoreactive neurons were mainly in telencephalic structures. Considerable overlap was observed between NK1 and NK3 receptor distributions. 3. Substance P induced Fos-like immunoreactivity (Fos-LI) in extensive areas of the guinea-pig brain. The induction of Fos-LI was markedly inhibited in many areas by pretreatment with the NK1 receptor antagonist SR 140333. The NK3 receptor antagonist SR 142801 reduced Fos-LI staining in fewer areas, although a reduction was observed in the cortex, striatum and hypothalamus. 4. In general, tachykinin receptors were located at sites corresponding to areas of functional activation by SP, as shown by Fos-LI. These results extend previous studies by adding a functional dimension to tachykinin receptor localization studies.
Yip
J
J
Experimental Pharmacology Unit, School of Biomedical Sciences, University of Newcastle, New South Wales, Australia.
Chahl
L A
LA
D000818:Animals; D001921:Brain / Q000033:anatomy & histology; D001923:Brain Chemistry / Q000187:drug effects*; D006168:Guinea Pigs; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D018040:Receptors, Neurokinin-1 / Q000187:drug effects / Q000378:metabolism; D018042:Receptors, Neurokinin-3 / Q000187:drug effects / Q000378:metabolism; D018039:Receptors, Tachykinin / Q000378:metabolism*; D013373:Substance P / Q000494:pharmacology*
D016760:Proto-Oncogene Proteins c-fos; D018040:Receptors, Neurokinin-1; D018042:Receptors, Neurokinin-3; D018039:Receptors, Tachykinin; D013373:Substance P