Effect of pigment dispersing hormone on the electrical activity of crayfish visual photoreceptors during the 24-h cycle

Visual photoreceptors are structures involved in the expression and synchronization of crayfish circadian rhythm of sensitivity to light (electroretinogram, ERG). Considering the relevant role of Pigment dispersing hormone (PDH) in the invertebrate circadian system organization, we study the effect of this substance on the electrical activity of crayfish visual photoreceptors during the 24-h cycle. The study demonstrates that: (1) PDH affects the electrical response to light of crayfish visual photoreceptor cells in a circadian time-dependent manner. (2) The kinetics of the light-elicited current of crayfish visual photoreceptor cells, as well as the ionic permeability underlying the electrical response to light vary over the 24-h cycle. (3) PDH modifies the kinetics and ionic permeability underlying the light-elicited current of crayfish visual photoreceptor cells in a circadian time-dependent manner.