An in vitro dispersed hypothalamic cell system was developed and utilized to investigate the effect of exposure to cold stress prior to sacrifice on release of somatostatin-like immunoreactivity (SRIF-LI). Exposure of the rats to cold stress prior to sacrifice significantly increased basal (or control) release of SRIF-LI from dispersed hypothalamic cells. The endogenous opiate peptides (beta-endorphin, Met-enkephalin and Leu-enkephalin)significantly inhibited the basal release of SRIF-LI from dispersed hypothalamic cells obtained from rats exposed to the cold prior to sacrifice. Naloxone, a specific opiate antagonist, had no effect on basal release but blocked inhibition by the endogenous opiate peptides. In marked contrast, the endogenous opiate peptides had no effect on basal release of SRIF-LI from dispersed hypothalamic cells of rats exposed to room temperature prior to sacrifice.