Several pharmacological and physiological studies have suggested that GABAA receptors (GABAA Rs) may exist in the rat major pelvic ganglion (MPG), a large coalescent pelvic ganglion that contains both sympathetic and parasympathetic components which innervates pelvic organs. However, the presence of GABAA R in the MPG has never been demonstrated directly by morphological studies. In the present study, we used immunohistochemistry to demonstrate the existence of GABAA R β2/3 subunits for the first time in the rat MPG. We also analyzed the neurochemical properties of MPG neurons expressing GABAA R β2/3 subunits. GABAA R β2/3-immunoreactive (-IR) neurons occupied 27.4 ± 7.0% of the whole neuronal population, and many of these (77.6%) were co-localized with tyrosine hydroxylase (TH). Likewise, most (86.5%) of TH-IR neurons were GABAA R β2/3-positive. GABAA R β2/3 subunits were also expressed in a few VIP- or NOS-IR neurons, the cholinergic or non-adrenergic, non-cholinergic (NANC) neurons. These results suggest that GABAA Rs are involved in the modulation of most sympathetic, noradrenergic neurons and also a subset of VIP and NOS neurons of the rat MPG.
Bibliographical noteFunding Information:
This work was supported by a grant of the Korea Health 21 R&D project, Ministry of Health & Welfare, Republic of Korea (03-PJ1-PG10-21300-0012) and 2005 Yonsei Research Center for Control of Autonomic Neural Plasticity. We would like to thank Mr. In Soo Lee and Mr. Dae Sung Park for their excellent technical supports.
All Science Journal Classification (ASJC) codes
- General Neuroscience