[The rapid effect of the iontophoretically applied cortisol on unit activity of neurons in three brain areas in rats].
The present study was undertaken to analyze whether the glucocorticoid (GC) effect was region specific in the brain. Na-cortisol-succinate (HC) was applied iontophoretically to cerebral cortex (CX), hippocampus (HPC) and PVN respectively and the effect on unit discharge rate in these three brain areas were compared. In cerebral cortex, the percentage of responsive neurons was only 8% (4/50), which was significantly lower than those in HPC (10/36, 27.8%) and PVN (9/35, 25.7%). The difference in the occurrence is paralleled with the known distribution of traditional GC cytosolic receptors in the brain. In all the three brain areas studied the main response to GC was inhibitory and the latencies of the responses were 9.6 +/- 6.5, 22.7 +/- 24.0, and 14.5 +/- 11.5 s and the durations of the after-effect were 74.8 +/- 66.5 (n = 4), 24.2 +/- 14.5 (n = 6) and 21.0 +/- 10.5 s (n = 9) respectively. The shortness of the latencies once again suggests that the mechanism involved is non-genomic. It is interest to note that in some HPC neurons the after-effect lasted for 1758 +/- 2148 s (n = 4). The results show that the rapid effect of GC on neurons is different in the three brain areas studied in regarding to the occurrence of responsive neurons and the duration of the after-effects.
Li
T Z
TZ
Department of Physiology, Second Military Medical University, Shanghai.
Wang
C A
CA
Chen
Y Z
YZ
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects; D004594:Electrophysiology; D006624:Hippocampus / Q000187:drug effects; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000494:pharmacology; D007478:Iontophoresis; D008297:Male; D009474:Neurons / Q000187:drug effects; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D011965:Receptors, Glucocorticoid / Q000378:metabolism
D011965:Receptors, Glucocorticoid; C007133:hydrocortisone hemisuccinate; D006854:Hydrocortisone