Ryugo Okagaki

Neural expression of a sodium channel gene requires cell-specific interactions

In the protochordate Halocynthia roretzi, voltage-activated sodium current undergoes a change in kinetics within 48 hr of fertilization. Molecular cloning and microinjection of antisense DNA into single cells suggest that the kinetic changes are due to the increased expression of a putative neural-specific sodium channel gene, TuNa I. TuNa I gene transcription is first induced in late stage gastrulae, preceding the appearance of the rapidly inactivating sodium current unique to neural cells. In cleavage-arrested and intact embryos, cell interactions between specific animal and vegetal blastomeres are required for induction of TuNa I gene expression. Our results implicate cell contact, prior to neurulation, as a mechanism for selectively activating the TuNa I gene expressed in cells of the neural lineage.

Stem cell factor (SCF) concentrations in peritoneal fluid of women with or without endometriosis.

PROBLEM: In the quest for possible involvement of stem cell factor (SCF), a cytokine known to have multiple effects, in the pathogenesis of endometriosis, we evaluated concentrations of SCF in peritoneal fluid (PF) of women with or without endometriosis.
 METHOD OF STUDY: SCF concentrations in PF collected from women undergoing laparoscopy were measured, using a specific enzyme‐linked immunosorbent assay (ELISA). Reverse transcription‐polymerase chain reaction (RT‐PCR) analysis to detect gene expression of c‐kit, the receptor for SCF, was performed using the endometriotic tissue and the eutopic endometrium collected during the operation.
 RESULTS: SCF concentrations in PF of women with endometriosis were significantly higher compared to women without endometriosis. Looking at SCF concentrations in PF of women with endometriosis stratified by disease stage, women with stage I and II exhibited relatively higher SCF levels in PF, whereas SCF levels in PF with stage III and IV were comparable with those without endometriosis. The expression of mRNA for c‐kit was detected in both the endometriotic tissue and the eutopic endometrium.
 CONCLUSION: We demonstrated an elevation in SCF levels in PF associated with endometriosis and the presence of its receptor in endometriotic tissues. Given the known pleiotropic properties of SCF, the present results suggest that SCF might play a role in the pathogenesis of endometriosis.

Successful laparoscopic treatment of ileo-cecal endometriosis producing bowel obstruction.

Bowel endometriosis manifesting with ileus is difficult to diagnose, often requiring laparotomy for diagnosis and treatment. We report here a case of ileo‐cecal endometriosis causing bowel obstruction. A diagnosis of intestinal endometriosis with menstruation‐associated bowel symptoms was made, and the patient was successfully treated by laparoscopic ileocecal resection.

Regulation of voltage-gated ion channels during ascidian embryogenesis.

In the proto-chordate Halocynthia roretzi, a voltage-activated sodium current undergoes a change in kinetics within 48 h of fertilization. Molecular cloning and microinjection of antisense DNA into single cells suggest that the kinetic changes are due to the increased expression of a neural-specific sodium channel gene, TuNa I. TuNa I gene transcription is first induced in late-stage gastrulae, preceding the appearance of the rapidly inactivating sodium current unique to alpha 4-2 derived neural cells. In cleavage-arrested and intact embryos, cell interactions between specific animal and vegetal blastomeres are required for induction of TuNa I gene expression. By contrast, another sodium channel gene, TuNa II, is mainly expressed in neural cells of the alpha 4-1 lineage. In this lineage, cells of endoderm, notochord and muscle develop. TuNa II gene transcription occurs in isolated alpha 4-1 blastomeres without interacting with other lineage cells. Thus, there are two distinct neural cell lineages in the ascidian tadpole: one is similar to the ectoderm-derived neural tissue controlled by a mechanism reminiscent of the neural induction in the vertebrate, the other is the lineage of posterior neural tube in which motor neurons develop in close association with the notochord or muscle lineage.

127 Expression of a calcium channel alpha1-subunit during neuronal and muscular differentiation of ascidian embryos

Masashi Umemiya To investigate dopaminergic modulation in the striatum, we recorded excitatory postsynaptic currents, evoked by local stimulation, from medium spiny neurons in postnatal rat brain slices. Recording were made using the whole-cell patch clamp technique under voltage-clamp condition. Incubation of slices in 1OmM dopamine resulted in a highly variable decrease in the amplitude of EPSCs. The variability of dopamine’s effect on EPSCs is consistent with activation of different receptor subtypes with potentially opposing effects. Incubation of slices in 5 mM SKF 386393, a Di-type dopamine receptor antagonist, resulted in potentiation of the EPSC. On the other hand, 5 mM SKF 386393 had no effect on currents activated by application of glutamate or kainate. However, because of the limitation of slow application of agonists, our results leave possibility that the effect of Di receptor activation on the EPSC is mediated via postsynaptic glutamate receptor modulation.