The Changes in the Expression of gamma-Aminobutyric Acid Related Enzymes in the Mouse Hippocampus Following Ketogenic Diet / 대한해부학회지

The ketogenic diet (KD) has been used to treat intractable childhood epilepsy. However, its mechanism of action remains unknown. In the present study, we examined the effects of KD on the expression of multiple constituents of the GABAergic system in the hippocampus through immunohistochemistry and northern blot analysis. From the results, we have shown that KD increased expression of GABA and decreased GABA transporter1 (GABATp) and GABA transaminase (GABA-T) mRNA levels in the hippocampus. These results suggest that the neuroinhibitory effect of KD may be mediated, at least in part, by the increment of GABAergic activity in the hippocampus. KD may increase the GABA levels in the synaptic space by limiting GABA reuptake and in the presynaptic nerve terminal by inhibiting GABA degradation.

Expression of pituitary adenylate cyclase activating polypeptide and its type I receptor mRNAs in human placenta

Pituitary adenylate cyclase activating polypeptide (PACAP) was first isolated from ovine hypothalamus and was known to stimulate the release of growth factor in various cells. Recently, we reported the cellular localization of PACAP and its type I (PAC1 ) receptor in rat placenta during pregnancy. Placenta is a critical organ that synthesizes several growth factors and angiogenic factors for the fetal development and its own growth. However, there is little information regarding the cellular localization of PACAP and its receptor in human placenta at various gestations. The aim of the present study was to define the expression and distribution of PACAP and PAC1 receptor mRNAs in the human placenta during the pregnancy period. PACAP and PAC1 receptor mRNAs were expressed in stroma cells of stem villi and terminal villi. At the early stage, on 7 and 14 weeks, PACAP and PAC1 receptor genes were moderately expressed in stroma cells surrounding the blood vessels within stem villi. These genes were strongly expressed in stroma cells of stem villi and terminal villi on 24 and 38 weeks. The expression of these genes was increased as gestation advanced, and localized in the same areas. Localization of PACAP and PAC1 receptor demonstrate the evidence that PACAP may play an important role, as an autoregulator or pararegulator via its PAC1 receptor. In conclusion, our findings strongly suggest that PACAP may have a critical role in physiological function of the placenta for gestational maintenance and fetal growth.

CNS cholinergic innervation to the hippocampus in the rat using pseudorabies virus as a neurotracer

The hippocampus is a central area of the memory-related neural system. Combined immunohistochemistry against choline acetyl transferase and retrograde transneuronal labelling of the pseudorabies virus were used to identify cholinergic neurons in the central nervous system projecting to the hippocampal formation of the rat. Five to ten microL of Bartha strain of pseudorabies virus were injected into the dentate gyrus, CA1 and CA3 of the hippocampus of 20 Sprague Dawley rats using stereotaxic instrument. Forty eight to 96 hr after the injection, the brains were removed and the tissue sections were processed for double immunofluorescence procedure using polyclonal antibodies against pseudorabies virus or choline acetyl transferase. The double labelled neurons were distributed at several different nuclei and the labelling patterns of three different areas of the hippocampus were similar. These data suggests that the cholinergic innervation to the hippocampus were distributed in a transsynaptic manner throughout the whole brain area.

Central Vagal Involvement in Ovarian Innervation of the Rat / 체질인류학회지

The mammalian ovary has been known as receiving its innervation by sympathetic and sensory neurons of the peripheral nervous system from the brain. Recently, there were several functional reports that the vagus nerves were also regulating the ovarian function, but the vagus nerve had not been identified by clear morphological evidence. A viral transneuronal tracing technique has been used to demonstrate the morphological evidence for the central vagal involvement in ovarian innervation in brain areas. Bartha strain of pseudorabies virus injection was made into the ovary of Sprague Dawley rats. In experimental group, the vagus nerve of the same injection side was removed right after ovarian injection. At five days after initial injection, all the rats were sacrificed and brains were processed for immunohistochemistry. Several central nuclei including hypothalamic paraventricular nucleus showed strong bilateral positive labelings after unilateral injection in control rats, but the positive labelings were disappeared or decreased in several hypothalamic nuclei and nuclei of the vagus nerve. In conclusion, these results provide the morphological evidence that vagus nerve has neural connection to ovary and by which the central nervous system may maintains the state of ovulation and reproduction as a possible parasympathetic routes in mammals.