ABSTRACT
The effects of resveratrol on the discharges of neurons in rat subfornical organ (SFO) slices were examined by using extracellular recording technique. The results are as follows: (1) In response to the application of resveratrol (1, 5, 10 mumol/L, n=65) into the superfusate for 2 min, the spontaneous discharge rate of 60/65 (92.3%) neurons was significantly decreased in a dose-dependent manner;(2) Application of L-glutamate (0.3 mmol/L) into the superfusate led to a marked increase in discharge rate of all 12 (100%) neurons in an epileptiform pattern. The increased discharges of 10/12 (83.3%) neurons were suppressed by application of resveratrol (5 mumol/L);(3) In 8 neurons, the selective L-type calcium channel agonist, Bay K8644 (0.1 mumol/L), induced a significant increase in discharge rate of all 8 (100%) neurons. The increased discharges of all 8 (100%) neurons were suppressed by resveratrol (5 mumol/L);(4) In 14 neurons, nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) 50 mumol/L significantly increased the discharge rate of 11/14 (78.6%) neurons. Resveratrol (5 ?mol/L) applied into the superfusate reduced the increased discharges of 9/11 (81.8%) neurons;(5) In 12 neurons, the large-conductance Ca(2+)-activated K(+) channel blocker tetraethylammonium chloride (TEA) 1 mmol/L significantly increased the discharge rate of 10/12 (83.3%) neurons. Resveratrol (5 mumol/L) inhibited the increased discharges of 9/10 (90%) neurons. These results suggest that resveratrol inhibits the electrical activity of SFO neurons. This effect may be related to its properties of blockade of L-type voltage-gated calcium channel and nitric oxide (NO) promoting, and probably has no association with large-conductance Ca(2+)-activated K(+) channel.