[Modulatory effects of 17beta-estradiol on the electrical activity of subfornical organ neurons].
The effects of 17beta-estradiol (E(2) ) on electrical activity of neurons in subfornical organ (SFO) slices were examined using extracelluar recording technique. The results are as follows. (1) In 15 SFO units, a low dose of E(2) (0.1 nmol/L) applied into superfusate induced an increase in discharge rate from 3.21+/-0.37 to 6.79+/-0.71 Hz (P<0.001), whereas a high dose of E(2) (100 nmol/L ) caused a decrease in discharge rate from 3.44+/-0.40 to 1.44+/-0.36 Hz (P<0.01); (2) glutamate NMDA receptor antagonist MK-801 (50 pmol/L) blocked the excitatory effects induced by low dose of 17beta-estradiol in 7 units; (3) L-arginine (L-arg, 1 mmol/L), a physiological precursor of NO, abolished the excitatory effects induced by low dose of 17beta-estradiol in 7 units; (4) application of N-omega-nitro-L-arginine methyl ester (L-NAME, 10 mmol/L), an inhibitor of NOS, blocked the inhibitory effects induced by high dose of 17beta-estradiol in 6 units. The above results suggest that the estrogen exerts dual action on SFO neuron. E(2) at low dosage increases the discharge rate of SFO neuron, an effect which may be related to the activation of NMDA receptors, whereas E(2) at high dosage decreases the discharge rate, an effect which may be attributed to the activation of NOS with resultant production of NO.
Wang
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Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017, China.
Wang
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D000818:Animals; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004594:Electrophysiology; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008297:Male; D009474:Neurons / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D013356:Subfornical Organ / Q000502:physiology*
D016194:Receptors, N-Methyl-D-Aspartate; D004958:Estradiol; D016291:Dizocilpine Maleate