Effects of Caffeine on the Crayfish Neuromuscular Junction

Abstract

The effect of caffeine on the nervous system was studied by exposing the crayfish neuromuscular junction to caffeine and stimulating nerves within proximity of glutamatergic synapses to elicit excitatory post-synaptic potentials (EPSPs), a measure of synaptic transmission. Previous work has shown that caffeine increases the probability of neurotransmitter release and increases the amount of available neurotransmitters in the pre-synaptic cell. Using a preparation of the fast extensor muscles in the tail of adult crayfish, we compared the amplitudes of the EPSPs elicited in 0.75, 1.00, and 1.25 mg of caffeine per liter of Ringers solution to the EPSPs elicited in normal Ringers solution. Observed trends and previous works suggest that caffeine increases EPSP amplitude and that this increase is time-dependent, concentration-dependent, and reversible; however, we were unable to show statistically significant conclusions from our data. Nevertheless, the trends we were able to see do support previous research concerning the effects of caffeine in other organisms.