Differing effects on the pre- and paravertebral sympathetic ganglia of adult mice produced by antisera to nerve growth factors from mice and snakes

Antiserum to nerve growth factor isolated from mouse salivary glands causes, in adult mice, a reduction of approximately 50% in weight of the superior cervical ganglia. Prevertebral ganglia are less sensitive than paravertebral ganglia. The reduction in weight of the superior cervical ganglia results from a reduction in size of the principal sympathetic neurones (mean diameter falling by approximately 30%) rather than from a reduction in both cell size and cell numbers. If, as seems to be the case in neonatal mice, the antiserum acts by neutralizing endogenous nerve growth factor, no effect on adult neurone numbers would be expected. The origin of the reduction in neurone size is not understood. Antisera to nerve growth factor isolated from snake venoms do not affect the superior cervical ganglia of adult mice. It is suggested that chemical differences between the snake venom and mouse salivary gland nerve growth factors might lead to differences in the antisera produced from these respective antigens.