Steroids modulate the excitability of crayfish (Procambarus digueti) photoreceptors: long- and short-term actions.
Short- and long-term actions of the steroids corticosterone, progesterone, and ecdysterone were analyzed upon excitability of crayfish retinular cells. The three hormones showed short-term actions, particularly during photoreceptor dark adaptation; effects were found to be dependent on the hour of the day. Corticosterone and progesterone had similar effects, i.e., resembled dark-adapted conditions; ecdysterone actions were opposite and resembled light adaptation. Long-term effects were opposed to short-term effects in all cases. Possible mechanisms underlying these effects are discussed.
Hernández-Falcón
J
J
Facultad de Medicina, U.N.A.M., México, D.F., 04510, Mexico.
Schneider-Ehrenberg
O
O
De la O Martínez
A
A
Campos-Lozada
V
V
Fuentes-Pardo
B
B
D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D003400:Astacoidea / Q000187:drug effects / Q000502:physiology*; D003315:Cornea / Q000187:drug effects / Q000502:physiology; D003345:Corticosterone / Q000008:administration & dosage / Q000494:pharmacology; D004441:Ecdysterone / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D008297:Male; D008564:Membrane Potentials; D010775:Photic Stimulation; D017956:Photoreceptor Cells, Invertebrate / Q000187:drug effects / Q000502:physiology*; D011282:Pregnenediones / Q000008:administration & dosage / Q000494:pharmacology*; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology; D013997:Time Factors
D011282:Pregnenediones; D011374:Progesterone; D004441:Ecdysterone; D003345:Corticosterone