Objectives:One of the prominent electrical and mechanical responses upon cessation of electrical field stimulation(EFS)in colonic smooth muscle is the rebound excitation(post-stimulus responses;PSR).However,little is ...
详细信息
Objectives:One of the prominent electrical and mechanical responses upon cessation of electrical field stimulation(EFS)in colonic smooth muscle is the rebound excitation(post-stimulus responses;PSR).However,little is known about the mechanisms underlying the ***,we believe that EFS induces nitric oxide(NO)release from enteric motor neurons,increases cyclic GMP(c GMP),activates protein kinase G and produces slow inhibitory junction potentials(s IJPs).The s IJPs are mediated by interstitial cells of Cajal(ICC).In the present study,we raised a new hypothesis that an increase in c GMP by NO in ICC inhibits phosphodiesterases,increases cyclic AMP and affects the ***,we investigated the role of various isoforms of c GMP-inhibited phosphodiesterases on PSR in murine colonic smooth ***:The proximal and distal colon was taken from C57/BL6(control),W/Wv,Pde3a KO,Pde3b KO and Pde4b KO *** microelectrode recordings of circular muscle were employed to investigate the *** tissue was subjected to a series of EFS with exogenous applications of atropine,L-NNA and ***:Molecular data by deep sequencing and quantitative PCR analysis showed that Pde3a transcripts are highly expressed in ICC.W/Wv mice displayed a reduction of PSR with a decrease in amplitude of s *** slow wave activity in the proximal colon was augmented in Pde3a KO tissue compared with ***-evoked excitatory junction potentials(EJP),s IJP and the PSR were significantly augmented in Pde3a KO *** pretreatment with atropine and MRS2500 did not affect PSR in both control and Pde3a KO *** additional application of L-NNA completely abolished the *** distal colon,Pde3a KO mice also showed a significant increase in ***3b and Pde4b KO mice had no significant phenotype in both proximal and distal *** was abolished by a protein kinase A(PKA)***:These data suggest that ICC have an important role in generating PS
Objectives:The firing of action potentials after IJPs has been described as rebound excitation(off-response)which increases with an increase in the frequency and train duration of electrical field stimulation(EFS)of e...
详细信息
Objectives:The firing of action potentials after IJPs has been described as rebound excitation(off-response)which increases with an increase in the frequency and train duration of electrical field stimulation(EFS)of enteric ***-stimulus responses(during stimulation)including EJP,fast IJP and slow IJP have been well characterized in previous *** little is known about the mechanisms underlying off(post-stimulus)responses(PSR).In the present study,we will characterize the PSR in murine proximal and distal ***:C57/Bl6 mice were used for intracellular microelectrode recordings from the smooth muscle of the proximal and distal ***,L-NNA and MRS2500 were applied to investigate the responses to electrical field stimulation(EFS).Results:In the proximal colon,EFS evoked excitatory junction potentials(EJP)followed by fast and slow inhibitory junction potentials(IJP).Upon cessation of EFS,PSR showed slow depolarization with spike *** pretreatment did not affect PSR suggesting that PSR is not due to cholinergic ***2500 treatment inhibited fast IJP but had no effect on PSR.L-NNA inhibited slow IJP and significantly decreased *** the distal colon,EFS evoked mainly fast IJP with small amplitude of slow IJP.L-NNA treatment had minimum effect on slow IJP and negligible effect on ***,MRS2500significantly decreased fast IJP and almost abolished ***:The two regions of the colon display different EFS-induced on-responses and *** responses in the proximal colon and purinergic responses in the distal colon are main factor to evoke *** nitrergic IJP and purinergic IJP are mediated by ICC and PDGFRα+cells,respectively,the different regional responses may be due to the density of ICC or PDGFRα+cell in the proximal colon and distal colon.
暂无评论