0000000001173124
AUTHOR
F. Mulè
Evidence that ATP or a related purine is an excitatory neurotransmitter in the longitudinal muscle of mouse distal colon
BACKGROUND AND PURPOSE: This study analysed the contribution of the purinergic system to enteric neurotransmission in the longitudinal muscle of mouse distal colon. EXPERIMENTAL APPROACH: Motor responses to exogenous ATP and to nerve stimulation in vitro were assessed as changes in isometric tension. KEY RESULTS: ATP induced a concentration-dependent contraction, reduced by 4-[[4-formyl-5-hydroxy-6-methyl-3-[(phosphonooxy)methyl]-2-pyridinyl]azo]-1,3-benzene disulphonic acid (PPADS), suramin, P2Y purinoreceptor desensitisation with adenosine 5'-O-2-thiodiphosphate (ADPbetaS), and atropine, but unaffected by P2X purinoceptor desensitisation with alpha,beta-methylene ATP (alpha,beta-meATP) an…
Myogenic NOS and endogenous NO production are defective in colon from dystrophic (mdx) mice
The aim of the present study was to evaluate whether alterations in the distribution and/or function of nitric oxide synthase (NOS) could be involved in the development of the spontaneous mechanical tone observed in colon from dystrophic (mdx) mice. By recording the intraluminal pressure of isolated colon from normal mice, we showed that Nω-nitro-L-arginine methyl ester (L-NAME) increased the tone, even in the presence of tetrodotoxin. The effect was prevented by L-arginine, nifedipine, or Ca2+-free solution. In colon from mdx mice, L-NAME was ineffective. Immunohistochemistry revealed that the presence and distribution of neuronal (nNOS), endothelial, and inducible NOS isoforms in smooth m…