Influence of Certain Neurotropic Substances on Central and Synatic Transmission in Callianassa

Abstract

Summary Eserine (2.5 × 10⁻⁵ M to 2.5 × 10⁻³ M) and atropine (2.5 × 10⁻³ M) produce a marked increase in the “spontaneous” activity of the ganglion cells of the ventral nerve cord of Callianassa californiensis. These substances have no appreciable effect on conduction characteristics of the giant fibers in the nerve cord, on the transmission across the synapse between the giant fibers and the nerves to the flexors of the telson, nor on denervated muscle. Nicotine (4 × 10⁻² M), methylamine (1 × 10⁻³ M), triethylamine (4 × 10⁻³ M) and di-isopropyl fluorophosphate (DFP) (1.3 × 10⁻² M) reversibly block synaptic transmission for varying periods of time.