Effects of resveratrol on intrinsic neuronal properties of CA1 pyramidal neurons in rat hippocampal slices

Resveratrol (3,5,4-trihydroxystilbene) a non-flavonoid polyphenol found in some plants like grapes, peanuts and pomegranates, possesses a wide range of biological effects. Evidence indicates that resveratrol has beneficial effects on nervous system to induce neuroprotection. However, the cellular mechanisms of the effects are not fully determined. In the present study, the cellular actions of resveratrol on intrinsic electrophysiological properties of the rat hippocampal CA1 pyramidal neurons were examined. The spontaneous and evoked firing properties of CA1 pyramidal neurons in adult rats exposed to resveratrol (100 µM) were examined using whole cell patch clamp recording under current clamp condition and the results were compared with control and vehicle treated groups. Treatment with resveratrol caused changes in neuronal firing characteristics. Application of resveratrol shifted the resting membrane potential (RMP) toward hyperpolarizing voltage (from -58.62±0.89 mV in control to -67.06±0.89 mV after resveratrol). The after hyperpolarization potential (AHP) amplitude was significantly (P < 0.001) increased following extracellular application of resveratrol. In addition, resveratrol treatment caused changes in evoked responses of pyramidal neurons. Its treatment induced a significant (P<0.05) increase in the peak amplitude of action potential in response to 100-300pA depolarizing current pulses. Furthermore, resveratrol-treated neurons displayed a significantly (P<0.05) increased time to peak in response to 400 and 500 pA depolarizing currents, when compared with either control or vehicle-treated groups. In addition, rise time to half-amplitude, rise tau and decay tau of action potential were significantly (P<0.01, P<0.01 and P<0.01, respectively) increased following resveratrol application. Resveratrol treatment changes the action potential parameters, hyperpolarizes the RMP and reduces the neuronal excitability and probably thereby may induce neuroprotective effects.