Transneuronal labeling from the rat distal colon: Anatomic evidence for regulation of distal colon function by a pontine corticotropin-releasing factor system

Abstract

Neural circuits that are positioned to regulate rat distal colon function were identified by immunohistochemical detection of pseudorabies virus (PRV) and corticotropin-releasing factor (CRF). The distribution of PRV-immunoreactive neurons was examined in spinal cord and brain at increasing times (72-118 hours) after distal colon injection. At 72-80 hours, PRV-labeling was confined to the spinal cord, in the parasympathetic preganglionic column in the lumbosacral spinal cord and in the intermediolateral column of the thoracic spinal cord. At longer survival times (88 hours), PRV-immunolabeled neurons in the lumbosacral spinal cord were also distributed in superficial layers of the dorsal horn, the dorsal commissure, and around the central canal. Trans-synaptic labeling was identified in the medullary raphe nuclei, parapyramidal region, A5, Barrington's nucleus, A7, and the dorsal cap of the paraventricular nucleus of the hypothalamus after longer survival times (88-91 hours). Substantial labeling of the locus coeruleus, periaqueductal gray and forebrain regions occurred at later survival times (> or = 96 hours). In dual-labeled sections, CRF terminal labeling surrounded PRV-labeled neurons in the parasympathetic preganglionic column of the lumbosacral spinal cord. Additionally, many neurons in Barrington's nucleus, but not other CRF-containing nuclei, were double labeled for CRF and PRV. These results, taken with previous studies, support a convergence in transneuronal labeling from different pelvic viscera that may be related to coordination of overall pelvic visceral functions. Importantly, they provide an anatomic substrate for an impact of CRF from Barrington's nucleus in normal and pathophysiological functions of the distal colon.

Stress and visceral pain: Focusing on irritable bowel syndrome

“…The paraventricular nucleus of the hypothalamus is part of a network by virtue of its projections to the pontine nuclei, such as the Barrington nuclei which have monosynpatic connections to sacral parasympathetic centers [80]. Through this…”

“…First, although research on molecular mechanisms [6,16,34,53,66,67,80] and microbiome mechanisms [63,70,81] is advancing rapidly, most studies have been conducted with rodents. Consequently, data from humans are still sparse.…”

Functional specializations within the tectum defense systems of the rat

“…Because frequency and NMDA stimulation of VLPAG failed to elicit defecation, this response seems to be organized in the LPAG, exclusively. Indeed, transneuronal retrograde labeling following the injection of pseudorabies virus into the distal colon of rats labeled a restricted region of the LPAG (Valentino et al, 2000).…”

“…Even though there is no consensus about the projections of PAG discrete columns to Barrington's nucleus, available evidence suggests extensive projections from DMPAG and central sectors of PAG abutting both the LPAG and VLPAG (Blok and Holstege, 1994;Ennis et al, 1991;Matsuura et al, 2000;Valentino et al, 1994Valentino et al, , 2000. These projections may be related to the wider areas from which the micturition can be elicited.…”

Identification of autonomic neuronal chains innervating gingiva and lip

“…Numerous data accumulated in the literature on the location of neurons in the central nervous system which are involved in the autonomic innervation of many viscera including the suprarenal gland (Strack et al, 1989a;Geerling et al, 2003;Tóth et al, 2008), the ovary , the kidney (Li et al, 1992;Schramm et al, 1993;Reichart et al, 2000;Valentino et al, 2000), the colon (Levatte et al, 1998;Vizzard et al, 2000), the penis, the prostate gland and the perineal muscles (Marson and Carson, 1999), the urinary bladder (RouzadeDominguez et al, 2003), the salivary (Jansen et al, 1992;Rezek et al, 2008) and mammary glands (Gerendai et al, 2001;Köves et al, 2012). As it was predicted by Strack and his co-workers (1989b), who injected a retrograde pseudorabies virus into various sympathetic ganglia and the adrenal gland, the premotor sympathetic neurons are generally found in several cell groups that regulate the entire sympathetic outflow: the hypothalamic paraventricular nucleus (PVN), perifornical region (Pf), A5 noradrenergic cell group, caudal raphe region, rostral ventrolateral medulla (VLM), the locus ceruleus (LC), and the Barrington's nucleus.…”