Immunohistochemical characterisation of pelvic autonomic ganglia in male mice

Abstract

Pelvic ganglia are mixed sympathetic-parasympathetic ganglia and provide the majority of the autonomic innervation to the urogenital organs. Here we describe the structural and histochemical features of the major pelvic ganglion in the male mouse and compare two different mouse strains. The basic structural features of the ganglion are similar to those in the male rat. Almost all pelvic ganglion cells are monopolar and most are cholinergic. All contain either neuropeptide Y (NPY) or vasoactive intestinal peptide (VIP), or both peptides together. The peptide coexistence varies between strains, with C57BL/6 mice having similar proportions of neurons with NPY alone, VIP alone or both peptides. In contrast, virtually all pelvic neurons in the Quackenbush-Swiss (QS) strain express NPY, i.e. the level of VIP/NPY coexistence is much higher. Cholinergic axons provide the major nerve supply to epithelia of reproductive organs, bladder smooth muscle and, as described previously, penile erectile tissue. They also provide a minor component of the smooth muscle innervation of the prostate gland, seminal vesicles and vas deferens. Virtually all non-cholinergic pelvic ganglion cells are noradrenergic and contain NPY. Their major target is smooth muscle of reproductive organs. This study shows that the male mouse pelvic ganglion bears many similarities to that in the rat, but that VIP/NPY colocalisation is much more common in the mouse. We also show that there are differences in peptide expression in parasympathetic pelvic neurons between strains of mice. These studies provide the framework for future investigations on neural regulation of urogenital function, particularly in transgenic and knockout models.

Neural Control of the Lower Urinary Tract

“…Many neurons are surrounded by ENK-IR varicosities (50%–65%) and fewer neurons are surrounded by CCK-or SOM-IR varicosities (30%–35%). The immunohistochemistry of the pelvic ganglia of the male mouse is similar to that of the rat (672). …”

Age-related changes in the innervation of the prostate gland

“…Dense neuropeptide Y innervation is found throughout the prostatic stroma of humans, 50 guinea pigs, rats 74 and mice 70 , 75 . However, there are conflicting reports concerning the expression of neuropeptide Y receptors in the prostates of humans 76 and rats 77 .…”

“…In various species the prostate receives a rich supply of vasoactive intestinal polypeptide (VIP) containing nerves, which are co-localized predominantly in cholinergic nerves innervating the prostatic glandular epithelium 10 , 11 , 75 . Receptors for VIP have been found in the prostate; 81 however due to their glandular distribution, VIP does not appear to be involved in contraction and instead may have roles in secretion or prostatic growth 82 …”

Neuropeptides in Lower Urinary Tract Function

“…These contradictory findings might be attributable to species differences (Uckert et al, 2002) and differential VIP receptor distribution (Table 19.1). The majority of VIP in the LUT is located in postganglionic efferent neurons of the pelvic ganglia (Chapple et al, 1992; Smet et al, 1997; Wanigasekara et al, 2003). Surprisingly, VIP had no apparent effects on either bladder tone or EFS-stimulated contractions despite VPAC 2 receptor transcript expression in detrusor (Braas et al, 2006).…”