Research Article

Behavioral Consequences of Delta-Opioid Receptor Activation in the Periaqueductal Gray of Morphine Tolerant Rats

Figure 3

Decrease in locomotion following microinjection of deltorphin into the vPAG. Microinjection of deltorphin (1 μg/0.5 μl) into the vPAG caused a decrease in locomotion in rats pretreated with morphine (N  =  13 and 9 for rats pretreated with 10 and 20 mg/kg) compared to rats pretreated with saline (N  =  11). This decrease in activity is caused by a change in normal behavior to lying and crouching in the cage following deltorphin administration (see Table 1).
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