Subpopulations of sympathetic neurones differ in their sensitivity to nerve growth factor antiserum.

Abstract

Sympathetic postganglionic nerve fibres supplying mesenteric arteries and intrinsic ileal neurones differ in their characteristics of regeneration. Since the latter population of neurones occurs predominantly in prevertebral ganglia, which have been reported to be spared to some extent after treatment with antiserum to nerve growth factor (anti-NGF), we have investigated whether the two populations were differentially sensitive to anti-NGF. Newborn rats were treated daily for the first postnatal week with either anti-NGF or 154 mM NaCl solution. At 4 and 8 weeks of age, the presence of a functional sympathetic innervation to the mesenteric arteries and the gut was determined and correlated with the fluorescence histochemical demonstration of noradrenergic fibres. At both ages, stimulation of extrinsic sympathetic fibres caused an inhibition of gut motility, while the mesenteric arteries completely lacked a sympathetic innervation. Retrograde labelling of nerve cell bodies in control and antiserum treated rats confirmed that the sympathetic neurones supplying the ileal neurones were located in the prevertebral, superior mesenteric and coeliac ganglia and in the splanchnic ganglia lying along the greater splanchnic nerves. By interference from retrograde labelling in control animals, sympathetic neurones supplying the mesenteric arteries were present in all these ganglia, as well as in the thoracic and lumbar paravertebral sympathetic chains. The results suggest that two functionally distinct populations of sympathetic neurones, which overlap considerably in their distributions, are differentially sensitive to the immunological postnatal removal of NGF.