Memory-enhancing effects in male mice of pregnenolone and steroids metabolically derived from it.
AUTOR(ES)
Flood, J F
RESUMO
Immediate post-training intracerebroventricular administration to male mice of pregnenolone (P), pregnenolone sulfate (PS), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androstenedione, testosterone, dihydrotestosterone, or aldosterone caused improvement of retention for footshock active avoidance training, while estrone, estradiol, progesterone, or 16 beta-bromoepiandrosterone did not. Dose-response curves were obtained for P, PS, DHEA, and testosterone. P and PS were the most potent, PS showing significant effects at 3.5 fmol per mouse. The active steroids did not show discernible structural features or known membrane or biochemical effects that correlated with their memory-enhancing capacity. The above, together with the findings that DHEA acted even when given at 1 hr after training and that P, PS, and DHEA improved retention over a much wider dose range than do excitatory memory enhancers, led to the suggestion that the effects of the active steroids converge at the facilitation of transcription of immediate-early genes. P and PS, for which receptors have not yet been demonstrated, may exert their effects by serving as precursors for the formation of a panoply of different steroids, ensuring near-optimal modulation of transcription of immediate-early genes required for achieving the plastic changes of memory processes. Low serum levels of P in aging and the increases of cancer and behavioral disorders in individuals receiving drugs that block synthesis of cholesterol, the immediate precursor of P, suggest possible clinical utility for P.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=48493Documentos Relacionados
- Adrenocortical suppression blocks the memory-enhancing effects of amphetamine and epinephrine.
- Memory-enhancing effects of secreted forms of the β-amyloid precursor protein in normal and amnestic mice
- Delayed emergence of effects of memory-enhancing drugs: implications for the dynamics of long-term memory.
- INDIGENOUS: IT DEPENDS HOW YOU LOOK AT IT. WHAT YOU CALL IT. HOW YOU LIVE IT
- Comparison of the virulent Asibi strain of yellow fever virus with the 17D vaccine strain derived from it.