Basic and Clinical Neuroscience Journal

en Effects of Neonatal C-Fiber Depletion on Interaction between Neocortical Short-Term and Long-Term Plasticity Cellular and molecular Neuroscience Cellular and molecular Neuroscience Original Original Introduction: The primary somatosensory cortex has an important role in nociceptive sensory-discriminative processing. Altered peripheral inputs produced by deafferentation or by long-term changes in levels of afferent stimulation can result in plasticity of cortex. Capsaicin-induced depletion of C-fiber afferents results in plasticity of the somatosensory system. Plasticity includes short-term and long-term changes in synaptic strength. We studied the interaction between paired-pulse facilitation, as one form of short-term plasticity, with long-term potentiation (LTP) in the neocortex of normal and C-fiber depleted freely moving rat. Methods: Neonatally capsaicin-treated rats and their controls were allowed to mature until they reached a weight between 250 and 300g. Then animals were anesthetized with ketamine and xylazine. For recording and stimulation, twisted teflon-coated stainless steel wires were implanted into somatosensory cortex or corpus callusom. In experiments for LTP induction, after two weeks of recovery period, 30 high frequency pulse trains were delivered once per day for 12 days. Paired-pulse ratio (PPR) was monitored before and after the induction of LTP in capsaicin-treated and control rats. Results: Paired-pulse stimulation affected all field potential components at intervals < 200 ms. The largest changes occurred at intervals between 20- 30 ms. C-fiber depletion postponed the development of LTP, whereas it had no effect on PPR. Discussion: This finding provides further evidence that the expression of this form of LTP is postsynaptic. Furthermore, these results suggest that the effect of C-fiber depletion on cortical LTP is also postsynaptic and, therefore, is not caused by a decrease in neurotransmitter release. Paired-Pulse Facilitation,Paired-Pulse Ratio,Long-Term Potentiation,C-fiber,Capsaicin,Plasticity. 136 145 http://bcn.iums.ac.ir/browse.php?a_code=A-10-1-153&slc_lang=en&sid=1 Alireza Komaki 1370031947532846003866 1370031947532846003866 Yes Siamak Shahidi 1370031947532846003867 1370031947532846003867 No Abdolrahman Sarihi 1370031947532846003868 1370031947532846003868 No Parisa Hasanein 1370031947532846003869 1370031947532846003869 No Reza Lashgari 1370031947532846003870 1370031947532846003870 No Abbas Haghparast 1370031947532846003871 1370031947532846003871 No Iraj Salehi 1370031947532846003872 1370031947532846003872 No