cDNA probes encoding preproenkephalin A (PPA) were used to detect the mRNA codings within the sections of adrenal glands of guinea pigs, processing according to the following procedures; perfused the animals with Zambonis' or 4% paraformaldehyde fixative; rinsed the block of adrenal glands for 12 hours in O.1mol/L phosphate sodium solution; the block were cut at -15℃ in a cryostat; Then the sections were prehybridized and hybridized with the biotinylated cDNA encoding PPA. The sections were incubated in the solution containing streptavi- din-biotinylated HRP and chromostained with DAB. The positive reactive produ- cts appeared in the cytoplasm of about 90% of adrenal medullary cells.

Objective　To investigate the possible roles of the different subnuclei of hypothalamic paraventricular nucleus （PNV） which may regulate splenic immune function. Methods　4 SD rats received splenic injection of pseudorabies virus（PRV）.96 hours after injection， a block containing hypothalamus was taken and cut into 40 μm sections with cryostat. Immunohistochemical technique and stereology method were used to detect the distributing character of transsynaptic PRV infection neurons in the PVN and the localization relationship between PRV neurons and AVP neurons in the PVN.Results　Transsynaptic PRV infection neurons distributed through out the PVN， but mainly concentrated in the lateral parvocellular （LP） subnucleus of PVN and posterior magnocellular （PM） subnuclei of PVN （occupied 73.49％ of total surface area），a few distributed in the anterior， dorsal and periventricular parvocellular （AP，DP and PP）nuclei of PVN，few scatted in the rest of nuclei of PVN. In the LP and PM some of the PRV neurons distributed among the AVP neurons.Conclusions　Besides the classical neuro-immuno-endocrine modulation， the PVN may regulate the splenic immune function through direct innervation .The AVP neurons in the PM and neurons projecting to the proganglionic neurons in the dorsal medulla and lateral horn of spinal cord in the LP，DP and AP regulate the immune function of spleen through sympathetic and para-sympathetic innovation.