0000000000522165
AUTHOR
M. Mastropaolo
THE ENTERIC NERVOUS SYSTEM: NEW DEVELOPMENTS AND EMERGING CONCEPTS
The enteric nervous system (ENS) is an integrative neuronal network, organized in two ganglionated plexuses, myenteric and submucosal, composed of neurons and enteric glial cells, controlling the activity of the smooth muscle of the gut, mucosal secretion and blood flow. The ENS contains as many neurons as the spinal cord, and the functional and chemical diversity of enteric neurons closely resembles that of the central nervous system. This highly integrated neural system is also referred to as the ‘brain-in-the-gut’, because of its capability to function in the absence of nerve inputs from the central nervous system.
Angiotensin II positively modulates the spontaneous contractile activity of mouse and human colon via activation of AT1 receptors.
Objective: Angiotensin II (Ang II) is a potent smooth muscle contractile neurohumoral agonist but has not been much investigated with regard to gastrointestinal motor activity. Ang II effects are mediated by specific receptors, the Ang II type 1 (AT1) and the Ang II type 2 (AT2) receptors, which are well expressed in the gut. In this study we evaluated the effects of Ang II on the contractile activity of longitudinal muscle from mouse and human colon and we analysed the subtype(s) of receptors involved in the observed effects. Methods: Mechanical responses to Ang II, in the absence or in the presence of different drugs, were assessed in vitro in colonic longitudinal muscle from mice and hum…
Role for D1-like and D2-like dopamine receptors in the modulation of intestinal motility in mice
Objective: In the last years a plethora of studies addressed dopamine (DA) as a modulator within the enteric nervous system (ENS), controlling gastrointestinal (GI) functions via activation of D1- and D2-like receptors. However, the effective role and functional significance of DA in the ENS, and the contribution of its receptors, are still a matter of debate. Pathological alterations of dopaminergic system in the gut may be likely implicated in different motor GI disorders, including dyspepsia and gastroparesis. Thus, a detailed characterization of the enteric dopaminergic signalling is necessary. The aim of this study was to explore the role of DA in the GI tract, using as model the mouse…
Opposite effects of dopamine on the mechanical activity of longitudinal and circular muscles in human colon
Objective: Dopamine (DA) has been proposed to act as a modulator of GI motility, via activation of specific receptors D1- and D2-like receptors widely expressed throughout the length of the gastrointestinal tract, in different animal species. However, little and not clear information are available about DA effect in the human gut. The aims of this study were to elucidate whether dopamine may affect contractility in human colon, the receptor subtypes involved and the possible differences in the function and distribution of dopaminergic receptors between longitudinal and circular muscle. Methods: Mechanical responses to dopamine were examined in vitro as changes in isometric tension in strips…