REEXAMINATION OF OPIOID STIMULATION OF CGMP FORMATION IN CELL-LINES OF NEURONAL ORIGIN

1. The present study reexamines a previous notion on opioid stimulatio n of cyclic GMP (cGMP) formation and the retraction of the original fi ndings. 2. The effect of opioid agonists on cGMP accumulation in two c ell lines of neuronal origin was measured. The proportion of cGMP stim ulation in NG108-15 neuroblastoma x glioma hybrid cells resembled the proportion of [Ca2+](in) elevation by opioids in this culture. The fai lure of opioids to stimulate cGMP formation in SK-N-SH human neuroblas toma coincided with the lack of cGMP stimulation by other Ca2+ mobiliz ing agents in these cells. The nitric oxide donor nitroprusside elevat ed cGMP in both cell lines. 3. The implication of the opioid-Ca2+-NO-c GMP cellular pathway for opioid activity in vivo is discussed.