GRIN1 and in situ carcinoma: In males, who did not develop oxycodone CPP, overall GluN1 density increased and so did GluA1 in the cytoplasm of CA3 dendrites and in the synapses of stratum radiatum spines, implying an enhanced glutamate binding capacity; in females, who developed oxycodone CPP, distribution of GluN1 remained similar to that of the saline treated CIS female group and GluA1 increased on the membrane of CA3 dendrites [121].