Methylphenidate and dopamine interact at the crayfish neuromuscular junction to modulate EPSP amplitude

Abstract

Our research explores the underlying neuronal mechanisms and effects of the neurotransmitter dopamine alone and in conjunction with methylphenidate, as well as methylphenidate by itself on the neurons excitatory postsynaptic potential at the crayfish neuromuscular junction. This topic examines the amplitude of the excitatory postsynaptic potential in four situations to uncover methylphenidates ability to switch dopamines effect from excitatory to inhibitory: when the neuromuscular junction is exposed to dopamine alone, dopamine then methylphenidate, methylphenidate then dopamine, and methylphenidate alone. Our results show that the amplitude of the excitatory postsynaptic potential (EPSP) at the crayfish neuromuscular junction increases when dopamine alone is present, and decreases when dopamine is added before methylphenidate, methylphenidate is added before dopamine, and methylphenidate is used alone. Dopamine, typically being an excitatory neurotransmitter, must then interact with methylphenidate in some way so that dopamines effects are swapped to produce an inhibitory response. Several studies, including our own, suggests that dopamine receptors are modulated by the presence of both dopamine and methylphenidate at the neuromuscular junction.