Transneuronal retrograde viral labeling in the brain stem and hypothalamus is more intense from the left than from the right adrenal gland.

Previous studies using the viral transneuronal tracing technique demonstrated central autonomic circuits involved in the innervation of the adrenal gland. Since increasing number of data indicate laterality in the neuroendocrine system, we aimed to investigate whether the supraspinal innervation of the adrenal gland exhibits asymmetry or not. The central circuitry involved in the innervation of the left and the right adrenal gland was studied in individual rats by dual transneuronal tracing using isogenic recombinant strains (Ba-DupGreen and Ba-Duplac expressing lacZ) of Bartha strain of pseudorabies virus.

Serotonin-synthesizing neurons in the rostral medullary raphé/parapyramidal region transneuronally labelled after injection of pseudorabies virus into the rat tail.

Serotonin-synthesizing raphé/parapyramidal neurons (5-HT neurons) may function as sympathetic premotor neurons regulating sympathetic outflow to the cutaneous vascular bed. In the present study a genetically engineered pseudorabies virus (PRV) expressing green fluorescent protein (GFP) was injected into the rat tail. After survival for 3-4 days the medulla oblongata was examined using double-label immunohistochemistry, with an antibody against GFP for the virus and an antibody against phenylalanine hydroxylase 8 (PH8) for 5-HT synthesis.