Steroid levels in tadpole (Rana catesbeiana) brain at the loss and return of the righting response.
Steroid levels were determined at the onset of anesthesia (tLRR) and at the recovery from anesthesia (tRRR). When 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha) was the administered agent, 3 alpha levels were similar at tLRR and tRRR1. The net rate of uptake of 3 alpha by the brain was approximately eight times the rate of loss of 3 alpha. Levels of 3 alpha were twice as high as tLRR when progesterone (PG) was the administered agent as when 3 alpha was used. The presence and absence of 0.1% ethanol in the incubation bath had no detectable effect on steroid levels. A model for the actions of 3 alpha is described. It is argued that interactions between 3 alpha and the target site are specific with respect to chemical structure and that the amount of 3 alpha in the compartment that contains the target sites is always small compared to that in whole brain.
Mok
W M
WM
Department of Anesthesia, Harvard Medical School, Brigham & Women's Hospital, Boston, MA 02115.
Krieger
N R
NR
D000758:Anesthesia; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D007814:Larva; D004856:Postural Balance / Q000502:physiology*; D011280:Pregnanolone / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D011892:Rana catesbeiana; D012018:Reflex / Q000502:physiology*; D013256:Steroids / Q000378:metabolism*
D013256:Steroids; D011374:Progesterone; D011280:Pregnanolone