Early and late effects of steroid hormones on the central nervous system.

摘要: Steroids have fast and probably partly GABA-mediated central anaesthetic effects for which a strict structure-function correlation is required. They also affect short- long-term activity in the CNS other ways. One of these potentiation (the persistent facilitation synaptic transmission), occurs particularly hippocampus after repetitive stimulation fibre pathway. Two clearly distinguished components evoked response can be studied hippocampus: excitatory postsynaptic potential (EPSP) denotes graded depolarization somadendritic region neuron population spike (PS), manifestation all-or-none discharge cell action potential. Corticosterone had significant depressant effect on EPSP component immediately 15 min injection. Thereafter amplitudes were within normal values. significantly decreased PS train, remaining low 30 train. 5 alpha-Dihydrocorticosterone (a ring A-reduced metabolite corticosterone) reduced at all times 18-Hydroxydeoxycorticosterone deoxycorticosterone both from time infusion. Contrary to expectation, tetrahydrodeoxycorticosterone was ineffective decreasing, if anything, enhanced development potentiation. 21-acetate behaved like vehicle, except first injection, when decreased. Different steroids selectively different parts appear show that required anaesthesia.