Chapter 6 Responsiveness of slowly adapting cutaneous mechanoreceptors after close arterial infusion of neomycin in cats

Abstract

This chapter compares the acute effects of neomycin on SA1 and SA2 receptors in cats with the aim of determining whether or not Merkel cells are the site of mechano-electric transduction in SAl receptors. Close arterial infusion of the aminoglycoside neomycin strongly suppresses the excitability of slowly adapting type 1 (SA1) cutaneous mechanoreceptors in the cat. Assuming that mechano-electric transduction takes place in the Merkel cells, there are two possible target sites for the action of neomycin, the transducer itself as well as the synaptic link between Merkel cell and nerve terminal. The greater reduction in responsiveness in SAl than in SA2 receptors is in support of the idea that in the SA1 receptors neomycin acts on two target sites: the mechanoelectric transducer in the Merkel cell and the putative synapse between the Merkel cell and the adjoining nerve terminal.