Endothelin-1 expression in myenteric neurons cultured from rat small intestine.
Endothelin is a potent vasoactive peptide. More recently, endothelin-1 (ET-1) has been found in neural tissues such as spinal cord, brain and peripheral ganglion cells. Inagaki (Gastroenterology 101 (1991) 47) reported evidence of ET-1-like immunoreactivity in enteric neurons, but there are no reports of ET-1 peptide or mRNA expression specifically in myenteric neurons. Using a primary culture of myenteric neurons, we set out to evaluate ET-1 peptide and mRNA expression. Myenteric neurons were cultured using a dissection and enzyme dispersion technique. ET-1 reactivity was localized to neurons and ET-1 levels from cells and media were assayed by radioimmunoassay under a variety of media conditions or with depolarizing buffer or veratridine (75 microM). Prepro ET-1 mRNA expression was determined by Northern analysis of total RNA utilizing a rat ET-1 cDNA. ET-1 immunoreactivity was observed almost exclusively in myenteric neurons. Cells contained 0.78 pg/micrograms protein and did not vary with variations in media conditions. Basal release/secretion into media occurred but was not enhanced by depolarizing media or veratridine. High levels of ET-1 mRNA expression were identified. These results of high level constitutive expression of ET-1 linked with previous reports of ET-1 modulation of cholinergic intestinal smooth muscle contraction suggest a neuromodulatory role.
Eaker
E
E
Department of Medicine, College of Medicine, University of Florida, Gainesville, USA.
Sallustio
J
J
Kohler
J
J
Visner
G
G
D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D015152:Blotting, Northern; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D016232:Endothelins / Q000096:biosynthesis* / Q000235:genetics; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D007421:Intestine, Small / Q000166:cytology / Q000294:innervation / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009119:Muscle Contraction / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology; D009197:Myenteric Plexus / Q000166:cytology / Q000378:metabolism*; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D014701:Veratridine / Q000737:chemistry
D016232:Endothelins; D012333:RNA, Messenger; D014701:Veratridine