Responses Of Sensory Cells Research Articles

Responses of maxillary sensilla styloconica inBombyx mori to glucosides fromOsmunda japonica, a nonhost plant

We isolated glucosides from the royal fern,Osmunda japonica, which elicit a deterrent response in larvae ofBombyx mori. These compounds were absent in taro (Colocasia antiquorum) and castor-oil plant (Ricinus communis) leaves and did not evoke responses of sensory cells in the lateral and medial sensilla styloconica ofSpodoptera litura. This glucoside extract of the royal fern leaves stimulates receptors generally associated with deterrent. It is also possible that this compound may act as a behavioral deterrent, and from actual feeding tests, it is suggested that this compound may prevent feeding in some monophagous insects, such asBombyx mori. The deterrent glucoside possesses a noncyclic aglycon.

Motile Responses of Vestibular Hair Cells Following Caloric, Electrical or Chemical Stimuli

Isolated, living vestibular hair cells (VHCs) from the guinea pig are capable of producing self-movements. Current injections and extracellular alternating current (a.c.) fields evoked mechanical responses of cell body or sensory hairs. Furthermore, superfusion in the presence of kainic acid or slow depolarizations by K-/gluconate evoked reversible slow motile responses of solitary vestibular sensory cells. If present in vivo, active VHC mechanics will influence the mechano-sensitive stereocilia and modulate stiffness and compliance of the receptor structure and its cupular or macular relationship. A tonic VHC motility might directly influence the displacement configuration in the cupula and macula organs and thus the micromechanical operating conditions of these sensory organs. Active mechanical events could contribute to adaptation processes (automatic gain control) and micromechanical non-linearities of stereociliary displacements. In addition, we demonstrate that direct caloric stimulation of isolated, living type I VHCs from guinea pig elicited mechanical responses of the sensory cells. This mechanism could contribute to the caloric induction of a nystagmus both under terrestrial and microgravitational conditions.