Microtubules and sensory transduction.

Cockroach legs bear tactile spines equipped with campaniform sensilla-mechanoreceptors associated with the cuticle-which function by a single bipolar neuron from whose dendrite tip extends a modified cilium packed with 350-1000 parallel cytoplasmic microtubules. These microtubules, which can be chemically disassembled with colchicine and vinblastine, are intimately associated with the site of mechanical stimulation. Treatment of living sensilla with colchicine and vinblastine abolishes their ability to respond to mechanical stimulation 1-2 hr after drug application. Loss of function is accompanied by large-scale disassembly of microtubules in the modified cilium. The experimental evidence strongly suggests that microtubules play an important role in the process of sensory transduction in campaniform sensilla.