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Neurokinin‐1 receptor localisation in guinea pig autonomic ganglia
Author(s) -
Messenger Jennifer P.,
Anderson Rebecca L.,
Gibbins Ian L.
Publication year - 1999
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19991004)412:4<693::aid-cne10>3.0.co;2-t
Subject(s) - substance p , tachykinin receptor , vasoactive intestinal peptide , biology , receptor , neuropeptide , tachykinin receptor 1 , neurokinin a , enkephalin , guinea pig , medicine , endocrinology , neuroscience , opioid , biochemistry
We have used multiple‐labelling immunohistochemistry and confocal microscopy to determine the distribution of immunoreactivity to the tachykinin neurokinin‐1 (NK 1 ) receptors in guinea pig sympathetic ganglia. Although nerve fibres containing immunoreactivity to substance P were common in all ganglia except the superior cervical ganglia, most neurons expressing NK 1 receptor immunoreactivity were not closely surrounded by pericellular baskets of substance P‐immunoreactive boutons. Conversely, many neurons surrounded by baskets of substance P‐immunoreactive boutons lacked NK 1 immunoreactivity. In the coeliac and inferior mesenteric ganglia, NK 1 receptor expression was restricted almost entirely to noradrenergic neurons that contained somatostatin immunoreactivity and projected to the enteric plexuses. In the lumbar chain and paracervical ganglia, NK 1 immunoreactivity was expressed by nonnoradrenergic vasodilator neurons containing immunoreactivity to vasoactive intestinal peptide. Taken together, our results show that sympathetic neurons in different functional pathways express NK 1 receptor immunoreactivity. However, the neurons that could respond to endogenously released substance P through NK 1 receptors may be distant from presynaptic release sites. These observations suggest that, in sympathetic ganglia, substance P may modulate ganglionic transmission through heterosynaptic actions on NK 1 receptors. J. Comp. Neurol. 412:693–704, 1999. © 1999 Wiley‐Liss, Inc.