抄録
The patch-clamp method has been applied to a wide variety of preparations. We also developed this method from in vitro and in vivo rat spinal cord preparations to understand the processing of sensory transmission. To address the sensory integration further, we performed in vivo patch-clamp recordings from somatosensory cortex neurons and analyze synaptic responses evoked by hindlimb stimulation. A rat was fixed in a stereotaxic apparatus under anesthetic (urethane or ketamine). Cranium of the rat was removed partially and surface of cortex was exposed. After making a bath with a plastic cup on a cranium hole, the surface of the brain was perfused continuously with Krebs solution. Under this condition, firstly, extracellular unit recordings were carried out for identification of the cortex that received inputs from the contralateral hindlimb. Patch-clamp recording electrodes were inserted into the location at where the unit firing frequency increased. Under the voltage-clamp mode at a holding potential of -70mV, spontaneous EPSCs were observed. The EPSCs frequency was increased by brush stimulation to the contralateral hindlimb. Under the current-clamp mode, the stimulation increased the frequency of action potential. These results indicate that the sensory information is transmitted not only to the spinal cord dorsal horn but also to the sensory cortex in rats anesthetized with anesthetics, suggesting a possibility that the sensory inputs are well preserved under the treatment with certain anesthetics. [Jpn J Physiol 54 Suppl:S175 (2004)]
