NPY-, galanin-, VIP/PHI-, CGRP- and substance P-immunoreactive neuronal subpopulations in cat autonomic and sensory ganglia and their projections

Abstract

The neuronal subpopulations in the cat stellate, lower lumbar and sacral sympathetic ganglia were studied with regard to the cellular distribution of immunoreactivity to tyrosine hydroxylase (TH), acetylcholinesterase (AChE) and various neuronal peptides. Coexistence of neuropeptide Y (NPY)- and galanin (GAL)-like immunoreactivity (LI) was found in a high proportion of the neuronal cell bodies; these cells also contained immunoreactivity to TH, confirming their presumably noradrenergic nature. Some TH- and GAL-immunoreactive principal ganglion cells lacked NPY-LI. Two populations (scattered and clustered) of vasoactive intestinal polypeptide (VIP)- and peptide histidine isoleucine (PHI)-positive cell bodies were found in the sympathetic ganglia studied. The scattered VIP/PHI neurons also contained AChE-LI, calcitonin gene-related peptide (CGRP)-and, following culture, substance P (SP)-LI. The clustered type only contained AChE-LI. In the submandibular and sphenopalatine ganglia, neurons were AChE- and VIP/PHI-immunoreactive but lacked CGRP- and SP-LI. Many GAL- and occasional TH-positive neurons were found in these ganglia. In the spinal ganglia, single NPY-immunoreactive sensory neuronal cells were observed, in addition to CGRP- and SP-positive neurons. The present results show that there are at least two populations of sympathetic cholinergic neurons in the cat. Retrograde tracing experiments indicate that the scattered type of cholinergic neurons contains four vasodilator peptides (VIP, PHI, CGRP, SP) and provides an important input to sweat glands, whereas the clustered type (containing VIP and PHI) mainly innervates blood vessels in muscles.

Sensory and Autonomic Neurons Project Both to the Smooth Retractor Penis and to the Striated Bulbospongiosus Muscles. Neurochemical Features of the Sympathetic Subset

“…This peptide has been already found in the STG of the sow (Panu et al, 2001;Ragionieri et al, 2008) and cat (Lindh et al, 1989) and in the RPM and BSM. (a, c, e, g, i, m, o, q, s, and u): DYþ/FBþ multipolar neurons of the left, ipsilateral, L7 or S1 STG.…”

“…Noradrenaline has been already documented in STG of the pig (Hill and Elde, 1989;Lakomy et al, 1994;Panu et al, 2001;Klimczuk, 2004), guinea-pig (Heym et al, 1990), rat (Kepper and Keast, 1997) and cat (Heym et al, 1984;Lindh et al, 1989).…”

“…STG of the pig (Hill andElde, 1989, Kaleczyc et al, 1993;Lakomy et al, 1994;Panu et al, 2001;Klimczuk, 2004), cat (Lindh et al, 1989), guinea-pig (Heym et al, 1990) and rat (Carrillo et al, 1991;Kepper and Keast, 1997).…”

“…These NPY-positive neurons certainly play a fundamental role in blood flow regulation (Gibbins, 1991), in fact NPY is a potent vasoconstrictor of many mammalian blood arteries (McLachlan and Llewellyn-Smith, 1986;Morris and Gibbins, 1987;Lindh et al, 1989;Lundberg et al, 1990;Majewski et al, 1995). Moreover, in the female NPY regulates also the contractile activity of nonvascular smooth muscle cells of the uterus and oviduct, as well as the secretory function of the ovary (Markiewicz et al, 2003).…”

“…This peptide is commonly considered a marker of afferent pathways (Majewski et al, 1995;Kaleczyc et al, 1997;Czaja, 2000), therefore, its presence within sympathetic neurons is an unforeseen finding. However, CGRP has been also shown in the STG neurons of the boar (Hill and Elde, 1989;H€ app€ ol€ a et al, 1993;Lakomy et al, 1994), sow (Panu et al, 2001;Ragionieri et al, 2008) cat (Kummer and Heym, 1988;Lindh et al, 1989) and horse (Nasu et al, 2003). Moreover, as there is some evidence that a minor proportion of CGRP-containing nerve fibers supply human genital organs (Jen et al, 1997), we think they might play a functional role in the modulation of neurotransmission in the target organs of the STG neurons (H€ app€ ol€ a et al, 1993).…”