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Nitric oxide (NO) released by myenteric neurons in isolated segments of guinea pig ileum was monitored in vitro using continuous amperometry. NO was detected as an oxidation current recorded with a boron-doped diamond microelectrode held at 1 V vs a Ag|AgCl reference electrode. This potential was sufficient to oxidize NO. Longitudinal muscle-myenteric(More)
BACKGROUND Inhibitory neurotransmission to the longitudinal muscle is more prominent in the neonatal than in the adult guinea pig ileum. METHODS Inhibitory neuromuscular transmission was investigated using in vitro ileal longitudinal muscle myenteric plexus (LMMP) preparations made from neonatal (< or =48 h postnatal) and adult ( approximately 4 weeks(More)
Alpha2-adrenoceptors inhibit Ca2+ influx through voltage-gated Ca2+ channels throughout the nervous system and Ca2+ channel function is modulated following activation of some G-protein coupled receptors. We studied the specific Ca2+ channel inhibited following alpha2-adrenoceptor activation in guinea-pig small intestinal myenteric neurons. Ca2+ currents(More)
P2X receptors are ATP-gated cation channels composed of one or more of seven different subunits. P2X receptors participate in intestinal neurotransmission but the subunit composition of enteric P2X receptors is unknown. In this study, we used tissues from P2X3 wild-type (P2X3+/+) mice and mice in which the P2X3 subunit gene had been deleted (P2X3-/-) to(More)
P2X receptors are ATP-gated cation channels composed of one or more of seven different subunits. ATP acts at P2X receptors to contribute to fast excitatory postsynaptic potentials (fEPSPs) in myenteric neurons but the subunit composition of enteric P2X receptors is unknown. These studies used tissues from P2X2 wild-type (P2X2+/+) and P2X2 gene knockout(More)
BACKGROUND & AIMS 5-Hydroxytryptamine (5-HT) is a neurotransmitter and paracrine signaling molecule in the gut. Paracrine signaling by enterochromaffin cells (EC), which release 5-HT, has not been studied in neonates. Our aim was to compare 5-HT disposition in the intestinal mucosa of neonatal and adult guinea pigs. METHODS 5-HT was locally measured in(More)
A diamond microelectrode was used to sensitively, reproducibly and stably record overflow of 5-hydroxytryptamine (5-HT, serotonin) from enterochromaffin cells (EC) of the intenstinal mucosal layer. 5-HT is an important neurotransmitter and paracrine signalling molecule in the gastrointestinal tract. The diamond microelectrode was formed by overcoating a(More)
Large-conductance Ca2+-activated potassium (BK) channels modulate vascular smooth muscle tone. Tempol, a superoxide dismutase (SOD) mimetic, lowers blood pressure and inhibits sympathetic nerve activity in normotensive and hypertensive rats. In the present study, we tested the hypotheses depressor responses caused by tempol are partly mediated by(More)
BACKGROUND Phytophthora sojae causes soybean root and stem rot, resulting in an annual loss of 1-2 billion US dollars in soybean production worldwide. A proteomic technique was used to determine the effects on soybean hypocotyls of infection with P. sojae. RESULTS In the present study, 46 differentially expressed proteins were identified in soybean(More)
Currents carried by L-, N-, and P/Q-type calcium channels do not account for the total calcium current in myenteric neurons. This study identified all calcium channels expressed by guinea pig small intestinal myenteric neurons maintained in primary culture. Calcium currents were recorded using whole cell techniques. Depolarizations (holding potential = -70(More)