Study on CNS Oxytocinergic Pathway Projecting to the Mammary Nerve of the Rat / 대한해부학회지

To identify the central innervating the mammary nerve, viral retrograde transneuronal labelling methods were employed. Pseudorabies virus 6 microliter was injected into the mammary nerve of adult female Sprague-Dawley rats. After 4 days of survival, the animals were perfused with 4% paraformaldehyde-lysine periodate and their brains were processed for immunohistochemistry and double immunofluorescent staining of Pseudorabies virus or oxytocin using polyclonal antibodies. Several nuclei in brain were retrogradely labelled with Pesudorabies virus.Only a few magnocellular neurons of the paraventricular nucleus throughout whole brain showed double immunoreactivity to Pseudorabies virus and oxytocin. Approximately 11 percent of the oxytocinergic cells of the paraventricular nucleus,especially in three subnuclei[dorsomedial cap, lateral magnocelluar part and ventral part] showed double positive reaction to both Pseudorabies virus and oxytocin. These data demonstrate that some CNS cells projecting to the mammary nerve contained oxytocin and it may acts as a neurotransmitter in this pathway and a hormone targeting milk production and secretion.

Central Neural Pathway for the Rat Tongue / 대한해부학회지

Bartha strain of pseudorabies virus[PRV-Ba] was utilized as a tracer to identify the neuronal axis of rat tongue muscles ; intrinsic muscles and extrinsic muscles, styloglossus, genioglossus, and hyoglossus muscle. After injection of 10 microliter of PRV-Ba into tongue muscles and 48-96 hours survivals, rats were perfused with 4% paraformaldehyde lysine periodate and brains were removed. PRV-Ba were localized in neural circuits by immunohistochemistry employing rabbit anti PRV-Ba as a primary antibody and ABC method. Injection of PRV-Ba into the tongue muscles resulted in uptake and retrograde transport of PRV-Ba in the rat brain. The result showed a circuit specific connection of many nerve cell groups along the time sequence : PRV-Ba immunoreactive cells appeared in hypoglossal nucleus and motor trigeminal nucleus ipsilaterally as seen with conventional tracers. Raphe nucleus, prepositus hypoglossal nucleus, spinal trigeminal nucleus, Al, A5 and facial nucleus of rhombencephalon showed immunoreactivity bilaterally. There were positive neurons in parabrachial nucleus, locus ceruleus, mesencephalic trigeminal nucleus, periaqueductal gray and A7 of mesencephalon and paraventricular nucleus, suprachiasmatic nucleus, organum vasculosum of lamina terminalis of diencephalon. Also positive reactions were showed in amygdala, insular cortex, frontal cortex and subfornical organ in telencephalon. Early immunoreactivity was appeared in hypoglossal nucleus and motor trigeminal nucleus, and there were positive neurons in the nuclei of the medulla oblongate, midbrain, pons, hypothalamus, cerebellum and medial preoptic area at middle stage. Subsequently the viral antigens were found in forebrain cell groups, paraventricular nuclei, suprachiasmatic nucleus, lateral hypothalamic area and primary motor cortex in frontal lobe bilaterally at 80-90hrs postinjection. These data demonstrate that the PRV-Ba can across synapses in the central nervous system with projection specific pattern, and this virus defines many elements of the neural network governing tongue. Therefore PRV-Ba are proved as a excellent neurotracer in the tract-tracing researches.