Is there an 'opposite' neurotransmitter to dopamine?
The release of dopamine has a positive effect on the reward center in the nucleus accumbens. The neuron that releases the dopamine can be inhibited by other neurons, so there gets less dopamine released.
The response elicited by a neurotransmitter, either excitatory or inhibitory, is determined by its receptor on the postsynaptic cell. ~https://www.ncbi.nlm.nih.gov/books/NBK21607/def-item/A7678/