Effect of opioid peptides on nervous tissue in vitro

: The effect of opioid peptides (gamma- and beta-endorphins, met- and leu-enkephalin, and 5 synthetic analogs of leu-enkephalin) was studied on organotypic culture of rat dorsal root ganglia and sympathetic ganglia. All peptides, except for one synthetic analog, were able to stimulate fibre outgrowth from explant, increase the numbers of glia and fibroblasttypic cells in the growth zone. The effect was observed in the range from 10(-10) to 10(-14)M. It is suggested that opioid peptides can be used as a nonspecific growth factor for nervous tissue.