ABSTRACT
Stress-induced gastric mucosal lesion (SGML) is one of the most common visceral complications after trauma. Restraint water-immersion stress (RWIS) can induce gastric mucosal lesion within a few hours. It has been confirmed that hyperfunction of parasympathetic nervous system contributes to the gastric dysfunction induced by RWIS. The dorsal motor nucleus of vagus, nucleus of solitary tract, hypothalamic supraoptic nucleus, paraventricular nucleus, mediodorsal thalamic nucleus, central amygdaloid nucleus and medial prefrontal cortex are all involved in the formation of SGML. Neurotransmitter/neuromodulation such as substance P, acetylcholine, oxytocin may be involved in the physiological process. This article reviewed the nervous mechanism of gastric mucosal lesion induced by RWIS in rats.
ABSTRACT
Restraint water-immersion stress (RWIS), a compound stress model, has been widely used to induce acute gastric ulceration in rats. A wealth of evidence suggests that the central nucleus of the amygdala (CEA) is a focal region for mediating the biological response to stress. Different stressors induce distinct alterations of neuronal activity in the CEA; however, few studies have reported the characteristics of CEA neuronal activity induced by RWIS. Therefore, we explored this issue using immunohistochemistry and in vivo extracellular single-unit recording. Our results showed that RWIS and restraint stress (RS) differentially changed the c-Fos expression and firing properties of neurons in the medial CEA. In addition, RWIS, but not RS, induced the activation of corticotropin-releasing hormone neurons in the CEA. These findings suggested that specific neuronal activation in the CEA is involved in the formation of RWIS-induced gastric ulcers. This study also provides a possible theoretical explanation for the different gastric dysfunctions induced by different stressors.
Subject(s)
Animals , Rats , Action Potentials , Physiology , Analysis of Variance , Central Amygdaloid Nucleus , Pathology , Corticotropin-Releasing Hormone , Metabolism , Disease Models, Animal , Gastric Mucosa , Pathology , Gene Expression Regulation , Physiology , Neurons , Physiology , Patch-Clamp Techniques , Proto-Oncogene Proteins c-fos , Metabolism , Rats, Wistar , Stress, Physiological , Physiology , Stress, PsychologicalABSTRACT
Objective To explore the effects of restraint water-immersion stress (RWIS) on the firing activities of pyramidal neurons in the medial prefrontal cortex (MPFC) of rats.Methods Multi-channel in vivo recording techniques were used to record firing activities of pyramidal neurons before and during 4-h RWIS in rats.Firing rates,inter-spike intervals and burst firing rates were taken as indices to study the influence of RWIS on neuronal firing activities.Results Twenty-five pyramidal neurons of 12 rats were recorded.The opposite patterns of firing activities were observed in two different classes of neurons,type A and type B neurons which account for 72％ and 28％,respectively.In type A neurons,inhibited firing activities were in direct proportion to the stress-exposure.Mean firing rates and mean burst firing rates were significantly reduced to (0.81 ± 0.11) Hz and (1.012 ± 0.50) counts/min after 4h constant RWIS compared with those before RWIS,(3.57 ± 0.63) Hz and (10.29 ± 3.04) counts/min.However,in type B neurons,firing activities were enhanced.After 2h constant RWIS,mean firing rates and mean burst firing rates were increased from (1.77±0.45) Hz and (2.01±0.73) counts/min to (2.67±0.74)Hz and (9.04±2.42) counts/min,respectively.Moreover,the percentage of spikes in bursts was significantly increased and mean inter-spike intervals were remarkably shortened.Interestingly,the effect of RWIS on type B neurons lasted for shorter time compared with its effect on type A neurons.Conclusion RWIS differentially affects the firing activity of pyramidal neuron in the MPFC,i.e.,inhibiting the firing activity of type A neurons,but enhancing the firing activity of type B neurons.