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Interstitial cells and cholinergic signalling in the outer muscle layers of the guinea‐pig bladder
Author(s) -
GILLESPIE JAMES I.,
MARKERINKVAN ITTERSUM MARJANNE,
DE VENTE JAN
Publication year - 2006
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1111/j.1464-410x.2006.05989.x
Subject(s) - choline acetyltransferase , cholinergic , acetylcholine , detrusor muscle , medicine , myocyte , cholinergic neuron , anatomy , urinary bladder , microbiology and biotechnology , biology
OBJECTIVES To explore the relationship between cholinergic mechanisms and interstitial cells (ICs) in the outer muscle layer of the bladder. MATERIALS AND METHODS In bladder tissue from male guinea‐pigs, ICs were identified by their response to nitric oxide (NO) with a rise in cGMP. Sections of the lateral bladder wall were incubated in Krebs’ solution containing 1 m m of the nonspecific phosphodiesterase inhibitor isobutyl‐methyl‐xanthene. Tissues were then exposed to 100 µ m of the NO donor NONOate for 10 min, control tissues remained in Krebs’ solution. Tissues were then processed for immunohistochemistry for cGMP, choline acetyltransferase (ChAT), neurofilament protein, and the nonspecific neuronal marker protein gene product (PGP) 9.5. RESULTS cGMP‐positive ICs were found mainly in the outer muscle layers of the bladder wall. Three types were identified based on location; on the outer surface of the bladder wall, on the surface of the muscle bundles, and within the muscle bundles. Some of the intramuscular ICs stained for ChAT, but they did not stain with PGP 9.5. Nerve fibres were seen in close contact with the ChAT‐positive intramuscular ICs, and these nerves expressed ChAT and neurofilament protein. CONCLUSIONS A subpopulation of intramuscular ICs can synthesise acetylcholine, and might release acetylcholine onto the underlying muscle. These cells are in close contact with nerves, suggesting that they might be activated by neural inputs. Thus there may be a system in the detrusor involving cholinergic nerves acting on ICs which can activate the smooth muscle via a complex cholinergic input.