Immunohistochemical characteristics of submucosal Dogiel type II neurons in rat colon |
| |
Authors: | Retsu Mitsui |
| |
Institution: | (1) Department of Health Science and Social Welfare, Faculty of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192, Japan |
| |
Abstract: | Secretory and motility reflexes are evoked by physiological stimuli in the isolated rat distal colon, which is therefore expected
to contain intrinsic primary afferent (sensory) neurons. Dogiel type II neurons (putative intrinsic primary afferent neurons)
exhibit several long processes emerging from large oval or round cell bodies. This study has examined the immunohistochemical
characteristics of type II neurons in the submucosal plexus of rat distal colons by using whole-mount preparations. Neuronal
cell bodies positive for both substance P (SP) and calretinin have been observed in colchicine-treated rats. Neurofilament
200 immunostaining has confirmed the type II morphology of SP-positive neurons. Moreover, all submucosal type II neurons identified
by neurofilament 200 immunoreactivity are positive for calretinin. Calcitonin gene-related peptide (CGRP)-positive neurons
in the submucosal plexus are distinct from type II neurons because they are negative for calretinin and have smaller cell
bodies than the SP-positive submucosal type II neurons. Most (73%) of the submucosal neurons including type II neurons exhibit
immunoreactivity for the neurokinin-1 receptor (NK1R), a receptor for SP, on the surface of cell bodies. Immunoreactivity
for the EP3 receptor (EP3R), a receptor for prostaglandin E2, has been detected in 51% of submucosal neurons including type
II neurons. Thus, submucosal type II neurons in the rat distal colon are immunopositive for SP/calretinin but immunonegative
for CGRP. SP released from submucosal type II neurons probably acts via NK1Rs on type II and non-type II submucosal neurons
to mediate intrinsic reflexes. EP3R-positive submucosal type II neurons may be potential targets of prostaglandin E2. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|