FUNCTIONAL POLARIZATION OF STATOCYST RECEPTORS IN THE CRAYFISH PROCAMBARUS-CLARKII GIRARD

Directionality of response in the statocyst receptors of the crayfish (Procambarus clarkii Girard) was investigated by artificially deflecting individual statocyst hairs in various directions. 1. The hairs attached to the receptors are aligned in a crescent on the statocyst floor. Hair deflection toward the center of the crescent elicited maximal excitatory responses in the majority of the receptors. Hair deflection in the opposite direction elicited maximal suppressive responses. 2. It was concluded that most of the statocyst receptors are functionally polarized toward the center of the crescent. The plane of functional polarization was consistent with that of morphological polarization. 3. The receptors could be classified into two types; tonic (42%) and phasic (50%), according to the time course of the excitatory responses. The remainder (8%) could not be classified as either of these, showing intermediate responses. 4. Some (ca. 40%) of the phasic-type receptors responded transiently regardless of the direction of hair deflection. It is suggested that the role of those receptors without any plane of functional polarization, is different from that of the other receptors in producing equilibrium responses. © 1979 Springer-Verlag.