The Anatomy, Histology, and Function of the Major Pelvic Ganglion

Simple Summary In male rats, the major pelvic ganglion is the principal component of the pelvic plexus and plays a crucial role in regulating various physiological functions such as urination, defecation, erection, ejaculation, and glandular secretion. This ganglion is considered mixed, as it receives both sympathetic and parasympathetic innervation through the hypogastric and pelvic nerves, respectively. Homologous structures with similar functions are present in other species, including cats, dogs, and pigs; however, differences exist in nomenclature, anatomical complexity, and functionality. Although anatomical, histological, and immunohistochemical studies have been conducted on these structures across various species, the major pelvic ganglion of the rat has been the most extensively studied due to its ease of identification and manipulation.Abstract This review provides a comprehensive analysis of the pelvic plexus and its regulation across various mammalian species, including rats, cats, dogs, and pigs. The pelvic and hypogastric nerves play crucial roles in regulating pelvic functions such as micturition, defecation, and erection. The anatomical organization of these nerves varies, forming either well-defined ganglia or complex plexuses. Despite these variations, the neurons within these structures are consistently regulated by key neurotransmitters, norepinephrine and acetylcholine. These neurons also possess receptors for testosterone and prolactin, particularly in rats, indicating the significant role of these hormones in neuronal function and development. Moreover, neuropeptides such as vasoactive intestinal peptide (VIP), substance P, neuropeptide Y (NPY), somatostatin (SOM), galanin (GAL), and calcitonin gene-related peptide (CGRP) are co-released with neurotransmitters to modulate pelvic functions. This review highlights the complex interplay between neurotransmitters, neuropeptides, and hormones in regulating pelvic physiology and emphasizes the importance of hormonal regulation in maintaining the functionality and health of the pelvic plexus across different species.