Tenotomy decreases sympathetic neuronal survival factors in avian smooth muscle

The expansor secundariorum of the chicken wing has a high concentration of survival factor activity for sympathetic neurons. The effect of tenotomy on this activity has been examined in newly hatched and older birds. Survival factor activity was assayed with dissociated embryonic neurons and found to be decreased after tenotomy to low levels in the newly hatched but not the older birds. No change in dopamine beta-hydroxylase concentration was detected, suggesting that tenotomy does not significantly alter impulse activity in the sympathetic innervation. The results are compared with findings after tenotomy in skeletal muscles and contrasted with increased survival factor activity produced by denervation of the expansor secundariorum.