Combined effect of early life stress and acute stress on colonic sensory and motor responses through serotonin pathways: differences between proximal and distal colon in rats.

Clinically, adults who have experienced stresses in childhood present with episodes of serious symptoms of irritable bowel syndrome that are associated with acute stress, but the mechanism is not well understood. This study aimed to investigate the colonic sensory/motor responses to acute water avoidance stress (WAS) in male adult rats subjected to neonatal maternal separation (NMS), and the underlying mechanism of sensory/motor responses. Effects of the combined acute and early life stress on visceral sensation, colonic motility, and the tissue and luminal content of serotonin (5-hydroxytryptamine, 5-HT) in the proximal and distal colon were evaluated using the abdominal withdrawal reflex test, faecal pellet output measurement and capillary electrophoresis analysis, respectively.

Quantification of luminally released serotonin in rat proximal colon by capillary electrophoresis with laser-induced fluorescence detection.

Serotonin (5-hydroxytryptamine, 5-HT) plays vital roles in regulating gastrointestinal functions. Thus, the detection of 5-HT in the gastrointestinal tract is of great importance for biomedical research, medical diagnosis, and pharmaceutical therapy. This paper presents a simple, sensitive, and fast method for the quantification of luminally released serotonin in the feces and tissues of the rat proximal colon by means of capillary electrophoresis with laser-induced fluorescence detection.

Sustained depolarization-induced propagation of [Ca2+]i oscillations in cultured DRG neurons: the involvement of extracellular ATP and P2Y receptor activation.

Recently emerging evidence implicates a number of neuroactive substances and their receptors in mediating complex cell-to-cell communications in the ganglia. In the present study, we characterized the nonsynaptic chemical coupling mediated by extracellular ATP in dorsal root ganglia (DRG) neuron cultures by using the real time imaging of ATP, whole-cell patch clamping, in conjunction with confocal calcium imaging. Sustained depolarization by electrical stimulation evoked intracellular Ca2+ concentrations ([Ca2+]i) oscillations in individual DRG neurons, and subsequent ATP-dependent propagation [Ca2+]i oscillations to surrounding non-stimulated neighbors.

Nerve growth factor inhibits Gd(3+)-sensitive calcium influx and reduces chemical anoxic neuronal death.

To investigate whether glutamate and voltage-gated calcium channels-independent calcium influx exists during acute anoxic neuronal damage and its possible relationship to neuronal protective function of NGF. In in vitro model of acute anoxia, hippocampal cultures from newborn rats were exposed to 3 mmol/L KCN. Changes of intracellular Ca(2+) concentration ([Ca(2+)](i)) were monitored by con-focal imaging and cell viability was assayed by PI and cFDA staining.

Repeated electro-acupuncture attenuates chronic visceral hypersensitivity and spinal cord NMDA receptor phosphorylation in a rat irritable bowel syndrome model.

Acupuncture has been used in clinical trials for the treatment of abdominal pain in patients with irritable bowel syndrome (IBS). However, scientific evidence is still lacking and the underlying mechanism remains largely unexplored. The aim of this study was to examine the effects of repeated administration of electro-acupuncture (EA) on chronic visceral hypersensitivity and on the phosphorylation of spinal cord N-methyl-D-aspartic acid (NMDA) receptors in a rat model of IBS.

TrkA pathway(s) is involved in regulation of TRPM7 expression in hippocampal neurons subjected to ischemic-reperfusion and oxygen-glucose deprivation.

The transient receptor potential melastatin 7 (TRPM7) is recently revealed playing a key role in anoxic neuronal death. Meanwhile, nerve growth factor (NGF), through activating TrkA pathway, has been widely accepted as a crucial factor for neuronal survival during cerebral ischemia. In this study, middle cerebral artery occlusion (MCAO) for 1h and reperfusion for 5, 10, 20 and 30 h revealed an increasing up-regulation of TRPM7 expression in ipsilateral hippocampus after reperfusion and such a change reached a peak at 20 h, with high expression being maintained up to 30 h.

NGF-induced reduction of an outward-rectifying TRPM7-like current in rat CA1 hippocampal neurons.

Transient receptor potential melastatin 7 (TRPM7) channels are widely expressed in the nervous system; however, their function and regulation are largely unknown. This study aimed to explore whether the current mediated by TRPM7-like channels in rat CA1 hippocampal neurons could be modulated by nerve growth factor (NGF). Using whole-cell patch clamp techniques, we identified an outward-rectifying TRPM7-like current in hippocampal neurons freshly isolated from postnatal (10-day-old) rats.

Effect of electroacupuncture on TRPM7 mRNA expression after cerebral ischemia/reperfusion in rats via TrkA pathway.

The effect of electroacupuncture (EA) on TRPM7 mRNA expression of focal cerebral ischemia in rats and further the role of EA in the relationship between TRPM7 and trkA pathway was investigated. Thirty SD rats were randomly divided into 5 groups : normal group, ischemia/reperfusion group, EA treated group (ischemic rats with EA treatment), TE infusion group (ischemic rats with EA treatment and TE buffer infusion), AS-ODN group (ischemic rats with EA treatment and antisense trkA oligonucleotide infusion). The stroke animal model was established by the modified method of middle cerebral artery occlusion.