Some evidence for the maturity of peripheral adrenergic nerves in newborn guinea pigs

The fluorescence histochemical technique of Falck and Hillarp revealed a similar distribution and density of peripheral adrenergic nerves in newborn and adult guinea pigs. The accumulation of tritiated noradrenaline by trachea from newborn guinea pigs, assumed to be uptake into adrenergic nerves, was not less than the accumulation by tracheae from adult animals. There was equal potentiation by cocaine (1x10M) of responses to noradrenaline on tracheal chain preparations taken from newborn and adult guinea pigs. The evidence supports the hypothesis that the guinea pig has a functional, well differentiated peripheral adrenergic nervous system at birth. This would account for the apparent inability to produce a long lasting sympathectomy by administration of 6 hydroxydopamine to newborn guinea pigs