Methods of electrophoretical application of estrogen to a single neuron of the brain under in vivo and in vitro conditions.

The techniques of the electrophoretical study of hormone sensitivities of neurons were examined in vivo and in vitro. For the in vivo study, estrogen and other hormones were applied electrophoretically to neurons of the rat brain of both sexes under urethane anesthesia. Some neurons were sensitive to estrogen and their activities were all inhibited. These neurons were distributed in the hypothalamus and the septal nucleus of the limbic system. So the in vivo method affords direct evidence for the presence of estrogen-sensitive neurons in the brain. Then a useful method was found to study the similar effects under the microscopic observations of a single neuron instead of stereotaxic insertion of the microelectrode. By this in vitro method the chemicals and hormones are able to be applied to any point on a single neuron through the micropipette and the medium composition around the neuron can be variously changed at the same time.