TY - JOUR
T1 - Inhibitory neuropeptides and intrinsic inhibitory innervation of descending human colon
AU - Koch, Timothy R.
AU - Carney, J. Aidan
AU - Go, V. L.W.
AU - Szurszewski, Joseph H.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1991/6
Y1 - 1991/6
N2 - The effects of aging on inhibitory neuropeptide concentrations and intrinsic inhibitory innervation of circular muscle were investigated using normal descending colon obtained at surgery. Immunoreactive vasoactive intestinal peptide, peptide histidine-methionine, met5-enkephalin, neuropeptide Y, and somatostatin were extracted from specimens of muscularis externa (patient ages: 19-84 years) and measured by radioimmunoassay. Intracellular electrical activity was recorded from strips of circular muscle (patients ages: 49-84 years) using glass microelectrodes; inhibitory junction potentials were evoked by electrical field stimulation. There were no significant differences (t tests:P>0.05) between neuropeptide concentrations in patients<70 years old (N=28) compared to patients≥70 years old (N=12). However, the amplitude of inhibitory junction potentials declined with increasing patient age (r=-0.58, P=0.02, N=16), with no change in resting membrane potentials (r=0.22;P>0.05). The decline in amplitude in women (r=-0.68, P=0.03, N=9) preceded the decline in men (r=-0.62, P=0.10, N=7). Age-related decline in inhibitory junction potentials could be related to decreased: density of inhibitory nerves, release of inhibitory neurotransmitter, density of binding sites for inhibitory neurotransmitter on smooth muscle, or a combination thereof. Alternatively, this decline might represent a change in interaction of inhibitory neurotransmitter with the smooth muscle membrane, such as a change in coupling of binding site with the potassium channel, decreased number of potassium channels, or altered permeability of the potassium channel.
AB - The effects of aging on inhibitory neuropeptide concentrations and intrinsic inhibitory innervation of circular muscle were investigated using normal descending colon obtained at surgery. Immunoreactive vasoactive intestinal peptide, peptide histidine-methionine, met5-enkephalin, neuropeptide Y, and somatostatin were extracted from specimens of muscularis externa (patient ages: 19-84 years) and measured by radioimmunoassay. Intracellular electrical activity was recorded from strips of circular muscle (patients ages: 49-84 years) using glass microelectrodes; inhibitory junction potentials were evoked by electrical field stimulation. There were no significant differences (t tests:P>0.05) between neuropeptide concentrations in patients<70 years old (N=28) compared to patients≥70 years old (N=12). However, the amplitude of inhibitory junction potentials declined with increasing patient age (r=-0.58, P=0.02, N=16), with no change in resting membrane potentials (r=0.22;P>0.05). The decline in amplitude in women (r=-0.68, P=0.03, N=9) preceded the decline in men (r=-0.62, P=0.10, N=7). Age-related decline in inhibitory junction potentials could be related to decreased: density of inhibitory nerves, release of inhibitory neurotransmitter, density of binding sites for inhibitory neurotransmitter on smooth muscle, or a combination thereof. Alternatively, this decline might represent a change in interaction of inhibitory neurotransmitter with the smooth muscle membrane, such as a change in coupling of binding site with the potassium channel, decreased number of potassium channels, or altered permeability of the potassium channel.
KW - age-related change
KW - human colon
KW - neuropeptide
KW - smooth muscle
KW - vasoactive intestinal peptide
UR - http://www.scopus.com/inward/record.url?scp=0025829231&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025829231&partnerID=8YFLogxK
U2 - 10.1007/BF01311226
DO - 10.1007/BF01311226
M3 - Article
C2 - 1674467
AN - SCOPUS:0025829231
SN - 0163-2116
VL - 36
SP - 712
EP - 718
JO - Digestive diseases and sciences
JF - Digestive diseases and sciences
IS - 6
ER -