L. Marson et al., CENTRAL-NERVOUS-SYSTEM INNERVATION OF THE PENIS AS REVEALED BY THE TRANSNEURONAL TRANSPORT OF PSEUDORABIES VIRUS, Neuroscience, 55(1), 1993, pp. 263-280
Transneuronal tracing techniques were used in order to identify putati
ve spinal interneurons and brainstem sites involved in the control of
penile function. Pseudorabies virus was injected into the corpus caver
nosus tissue of the penis in rats. After a four day survival period, r
ats were perfused with fixative and virus-labelled neurons were identi
fied by immunohistochemistry. Postganglionic neurons were retrogradely
labelled in the major pelvic ganglia. In the spinal cord, sympathetic
and parasympathetic preganglionic neurons were labelled transneuronal
ly. Presumptive interneurons were also labelled in the lower thoracic
and lumbosacral spinal cord in locations consistent with what is curre
ntly known about such interneurons. In the brainstem, transneuronally
labelled neurons were found in the medulla, pons and hypothalamus. Reg
ions consistently labelled included the nucleus paragigantocellularis,
parapyramidal reticular formation of the medulla, raphe pallidus, rap
he magnus, A5 noradrenergic cell group, Barrington's nucleus and the p
araventricular nucleus of the hypothalamus. This study confirmed previ
ous studies from our lab and others concerning the preganglionic and p
ostganglionic neurons innervating the penis. The number, morphology an
d location of these neurons were consistent with labelling seen follow
ing injection of conventional tracers into the penis. The brainstem nu
clei labelled in this study were also consistent with what is currentl
y known about the brainstem control of penile function. The labelling
appeared to be highly specific, in that descending systems involved in
other functions were not labelled. These results provide further evid
ence that the pseudorabies virus transneuronal tracing technique is a
valuable method for identifying neural circuits mediating specific fun
ctions.