The neuropeptide DF₂ decreases the EPSP amplitude in the crayfish neuromuscular junction with a lessened effect at lower temperatures and with crayfish chronically exposed to lower temperatures

Abstract

The neuropeptide DRNFLRFamide (DF₂) has been shown to increase the amplitude of the excitatory post-synaptic potential (EPSP) in crayfish with a greater effect at lower temperatures. We studied the effect of DF₂ on the EPSP amplitude at the neuromuscular junction in crayfish when placed in a saline solution at 7-9 degrees Celsius and at 20-22 degrees Celsius. The crayfish were from two different populations; one was exposed to a chronically cold environment (7-9 degrees) and another was exposed to a chronically warm environment (20-22 degrees.) Our data suggests that the EPSP amplitude tends to decrease when exposed to DF₂, however there is a less significant decrease when the crayfish is exposed to DF₂ at lower temperatures and in crayfish chronically exposed to low temperatures.