Very tight contact of tormogen cell membrane and sensillum cuticle: ultrastructural basis for high electrical resistance between receptor-lymph and subcuticular spaces in silkmoth olfactory hairs

A very tight contact is present between the apical membrane of the tormogen cell and the cuticle of the hair base in olfactory sensilla trichodea of Antheraea polyphemus. The contact zone is characterized by numerous hemidesmosome-like structures of the cell membrane, which closely attach the latter to the cuticle. If apically opened hairs are incubated in a LaCl3 solution, the tracer ions do not penetrate the contact zone. It is concluded that the tight contacts are the morphological correlates of the electrical isolation of the receptor-lymph space (cf. de Kramer et al., in press).