The Langerhans receptor of Oikopleura (Tunicata: Larvacea)

Abstract

The bristle-bearing receptors on either side of the trunk in Oikopleura are connected to the caudal ganglion by the axons of central cells which form electrical synapses (gap junctions) at the bases of the receptor cells. The same axons also form similar synapses with epithelial cells adjacent to the receptors. Direct mechanical stimulation of the receptor processes evokes changes in the locomotor rhythm of the same kind as evoked by action potentials propagated in the epithelial cells. This remarkable arrangement is suggested to be a consequence of the reduced numbers of cells in larvaceans.