ABSTRACT
Using conventional electrophysiological technique, we investigated the effects of stimulating the medial prefrontal cortex (mPFC) on plasticity of frequency receptive field (RF) in auditory cortical (AC) neurons in rats. When the mPFC was electrically stimulated, the RF plasticity of 51 (27.2%) neurons was not affected and that of 137 neurons (72.8%) was either inhibited (71 neurons, 37.7%) or facilitated (66 neurons, 35.1%). The modulation of RF plasticity by the stimulation of mPFC was dependent upon the time interval between acoustic and electrical stimuli. The best interval time that produced optimal modulation (inhibition or facilitation) ranged from 5 to 30 ms. The inhibitory modulation of mPFC prolonged RF shifting time and shortened RF recovery time. Conversely, the facilitatory modulation of mPFC shortened RF shifting time and prolonged RF recovery time. Our results suggest that the mPFC may affect the plasticity of functional activity in AC neurons, and also may participate in the process of auditory learning and memory.
Subject(s)
Animals , Rats , Auditory Cortex , Cell Biology , Electric Stimulation , Neuronal Plasticity , Neurons , Physiology , Prefrontal Cortex , PhysiologyABSTRACT
<p><b>OBJECTIVE</b>To investigate the protective effect of glycine (Gly) on hypoxic rat myocardial cells and its mechanism.</p><p><b>METHODS</b>Sdfetal rat myocardial cells were isolated and cultured in vitro. The released amounts of creatine kinase (CK) and lactate dehydrogenase (LDH) from the myocardial cells in the culture supernatant at 6 hour after hypoxia and after glycine treatment were determined with ultraviolet spectrophotometer. The expression of the alpha1 subunits of glycine receptor (GlyRalpha1) in the myocardial cells was detected by immunofluorescent histochemistry. The changes in the intracellular calcium content and the membrane potential of the myocardial cells were determined by laser confocal microscopy.</p><p><b>RESULTS</b>The release of CK and LDH in the culture supernatant increased significantly at 6 h after hypoxia [(393.8 +/- 5.3), (1564 +/- 41) U/L] compared with those before hypoxia, while their levels were obviously decreased after glycine treatment [(56.3 +/- 2.7), (716 +/- 18) U/L, (P <0.01)] compared with those before glycine treatment. There was positive expression of GlyRalpha1 in myocardial cells before and after hypoxia. The average fluorescent intensity of intracellular calcium at 6 hours after hypoxia (139 +/- 29) was significantly higher than that before hypoxia (27 +/- 8, P < 0.01), while it was obviously lower (51 +/- 11) after glycine treatment compared with that at 6 hours after hypoxia,but it was evidently higher than that before hypoxia (P <0.01). The membrane potential 6 hours after hypoxia (62 +/- 9) was obviously lower than that before hypoxia (177 +/- 20, P < 0.01), but it was obviously higher after glycine treatment (123 +/- 16) than that at 6 hours after hypoxia (P < 0.01).</p><p><b>CONCLUSION</b>Glycine might be beneficial in the protection of myocardial cells against hypoxia. The underlying mechanism may involve attenuation of membrane potential depolarization after hypoxia by conjugation of glycine with its receptor, depleting in turn voltage-dependent calcium channel on the cellular membrane, preventing calcium overload due to influx of calcium ions after hypoxia.</p>
Subject(s)
Animals , Rats , Calcium , Metabolism , Cell Hypoxia , Cells, Cultured , Creatine Kinase , Metabolism , Glycine , Pharmacology , L-Lactate Dehydrogenase , Metabolism , Membrane Potentials , Myocytes, Cardiac , Cell Biology , Rats, Sprague-DawleyABSTRACT
Objective:To study whether the orientation behavior of rats is affected by multi-sensory information.Methods: SD rats were randomly divided into 2 groups:the audio-visual integration group and pure audio group.The orientation behaviors of rats were observed after given single modal and multi-modal sensory cues with spatial disparities.Results:We found that when the temporal and spatial audio cues were coincident to a target visual cue,the rats had a markedly reduced reaction time and increased success rate in orientation behaviors;there was an obvious audio-visual integration effect.The integration effect was more obvious when the intensity of target visual cue was weak,with the enhancement efficiency being(87.3?8.5)%, significantly higher than that when the intensity of target visual cue was stronger(27.6%,P