Morphological changes in network of enteric nerve-interstitial cells of Cajal-smooth muscle cells in rats with multiple organ dysfunction syndrome and therapeutic effects of Dachengqi decoction (大承气汤) / 中国结合医学杂志

<p><b>OBJECTIVE</b>To observe the effects of Dachengqi Decoction (大承气汤, DCQD) on morphological changes in the network of enteric nerve-interstitial cells of Cajal (ICCs)-smooth muscle cells (SMC) of enteric deep muscular plexuses (DMP) in the rats with multiple organ dysfunction syndrome (MODS).</p><p><b>METHODS</b>One hundred Wistar rats of both sexes weighing 200 to 250 g were randomly divided into the control group, MODS group, and DCQD group. The morphologic changes of enteric nerve-ICC-SMC network in the DMP of intestine was observed using c-Kit and vesicular acetylcholine transporter/neuronal nitric oxide synthase immunohistochemical double-staining with whole-mount preparation technique, confocal laser scanning microscopy, and electron microscopy.</p><p><b>RESULTS</b>Compared with the control group, the distribution and densities of cholinergic/nitrergic nerves and ICC in the DMP (ICC-DMP) of intestine in the MODS group were significantly decreased (P<0.01), and the network of cholinergic nerve-ICC-SMC was disrupted; and the ultrastructural features of ICC-DMP, enteric nerve, and SMC were severely damaged. After treatment with DCQD, the damage in the network of enteric nerve-ICC-SMC was significantly recovered. Compared with the MODS group, the distribution and densities of cholinergic/nitrergic nerves and ICC-DMP in the DCQD group were significantly increased (P<0.01); and the ultrastructural features of ICC-DMP, enteric nerve, smooth muscle cells were significantly recovered.</p><p><b>CONCLUSIONS</b>DCQD can improve the gastrointestinal motility in MODS. The mechanism may be related to the effect of repairing the damages in the network of enteric nerve-ICC-SMC.</p>

Effects of purinergic analogues on spontaneous contraction and electrical activities of gastric antral circular muscle in guinea-pig / 生理学报

In order to investigate the role of non-adrenergic non-cholinergic nerves in regulating mechanical and electrical activity of gastric circular smooth muscle, the effects of ATP and its analogues on gastric motility and electrical activities were observed in guinea-pig. In organ bath system, isometric force of the circular smooth muscle of guinea-pig gastric antrum was measured. Electrical activity of the muscle was recorded by using intracellular microelectrode. Electrical and mechanical activities were recorded by chart recorder. ATP and 2-MeSATP potentiated the mechanical activity but did not affect electrical activity in gastric circular smooth muscle. ATP and 2-MeSATP-induced contraction was effectively blocked by nonselective P2y-purinoceptor antagonist, reactive-blue-2 and suramin, but ATP-induced contraction was not blocked by alpha,beta-MeATP-induced desensitization of P2x-purinoceptors. However, alpha,beta-MeATP, P2x-purinoceptor agonist, attenuated slow waves with membrane hyperpolarization and inhibited contraction. The relaxation by beta,gamma-MeATP was blocked by alpha,beta-MeATP-induced desensitization of P2x-purinoceptors. ATP-induced contraction was blocked by external calcium-free, but not by nicardipine, a L-type calcium channel blocker. Indomethacin, a nonselective cyclooxygenase inhibitor, did not block ATP-induced contraction. The results suggest that: (1) ATP- and analogues-induced contraction is mediated by P2y-purinoceptor, whereas alpha,beta-MeATP-induced relaxation by P2x-purinoceptor in guinea-pig gastric antral circular smooth muscle. (2) ATP-induced contraction is dependent on extracellular calcium, but Ca2+ entry is not mediated by L-type calcium channel. (3) Prostaglandins are not involved in ATP- and analogue-induced contraction of gastric circular smooth muscle in guinea-pigs, and alpha,beta-MeATP-induced relaxation is related to membrane hyperpolarization.

Role of actin microfilament in hyposmotic membrane stretch-induced increase in muscarinic current of guinea-pig gastric myocytes / 生理学报

To investigate the relationship between cytoskeleton and hyposmotic membrane stretch-induced increase in muscarinic current, the role of actin microfilament in hyposmotic membrane stretch-induced increase in muscarinic current was studied with the whole-cell patch clamp technique in guinea-pig gastric myocytes. In this study, the muscarinic current was induced by carbachol (50 micromol/L) or GTPgammaS (0.5 mmol/L). The results showed that hyposmotic superfusate (202 mOsmol/L) increased carbachol-induced current (I(CCh)) by 145+/-27% and increased GTPgammaS-induced current by 183+/-30%; but in the presence of cytochalasin-B (Cyt-B, 20 micromol/L), an actin cytoskeleton disruptor, hyposmotic membrane stretch increased I(CCh) by 70+/-6%. However, hyposmotic membrane stretch induced increase in I(CCh) was potentiated to 545+/-81% by phalloidin (20 micromol/L), an actin microfilament stabilizer. The results demonstrated that hyposmotic membrane stretch increased the muscarinic currents induced by carbachol or GTPgammaS and that the actin microfilament is involved in the process in guinea-pig gastric myocytes.