A classification of NOergic neurons in the inferior colliculus of rat according to co-existence with classical amino acid transmitters.

Since the localization of nitric oxide synthase (NOS) can be identified by enzyme histochemistry for NADPH-diaphorse (NADPH-d), this method has been used widely for mapping NOS-containing (presumably NOergic) neurons in the central nervous system. So far several studies suggest that NADPH-d is present in distinct neuronal populations in the inferior colliculus (IC), a major processing center for both the ascending and descending auditory pathway, and NO may play an important role in audition. On one hand, there is evidence from several lines of research that the IC makes extensive use of the neuroactive amino acids, in particular the inhibitory transmitter g-aminobutyric acid (GABA) and the excitatory amino acid glutamate (GLU). However, lacking is a description of the distribution of NOergic neurons to which traditional neurotransmitters may be linked. The present research utilized NADPH-d enzyme histochemistry in combination with immunocytochemistry to determine if NO may colocalize with either or both GABA and glutamate in distinct subpopulations of IC neurons. The NADPH-d positive neurons were predominantly found in two main subdivisions of the IC: the external cortex (ECIC) and the dorsal cortex (DCIC). The large numbers of these NADPH-d positive neurons appeared immunostained for GLU while only a small number, seemed to belong to the small cells (somatic area < 100 microm2) similarity to stellate cells group was positive for GABA throughout the cortex of the IC. Owing to no coexistence between GABA and GLU in the same NADPH-d positive neuron in the pairs of adjacent sections of the IC by the mirror-image technique, the present results consequently support that NOergic neurons could be subdivided into at least three distinct populations with a large proportion of about 77% being GLUergic, much lower frequency of about 11% being GABAergic and the remaining 12% expressing non-GABA and non-GLU. In summary, the existence of two functionally distinct populations of NO/GABAergic and NO/GLUergic neurons in the NOergic neurons of IC suggest that at least two differential pattern of GLU-mediated excitatory NO transmission and GABA-mediated inhibitory NO transmission are involved in the networking of auditory communication in the cortex of IC.

["Restricted ablation" of elongated uvula mucosa by the injection of the ethanol/steroid mixture: a new treatment for snoring and OSAS].

We developed a "Submucosal Ethanol/Steroid (E/S) Injection Method (SEIM)" using an injection prepared by dissolving steroid with powerful antiinflammatory effect, which has the excellent effect of contractile reduction in oral tissues. In this clinical trial, the ablation effect of SEIM on the abnormally elongated uvula and the soft palate was examined in each one clinical case of obstructive sleep apnea syndrome (OSAS) and simple snoring. In the OSAS, we found that the uvula was reduced from 15 to 10mm, the visual analog scale (VAS) of snoring was reduced from 10 to 4 points, and the respiration disturbance index of the apnea-hypopnea index (AHI) improved from 35.3 to 26.1 after treatment. In simple snoring, the uvula was reduced from 11 to 8.5mm and VAS was relieved from 7 to 2 points after treatment. Our approach will produce a great clinical significance for not only OSAS or simple snoring but also treatment of the allergic rhinitis, etc, because the contractile tissue reduction can be attained safely in these diseases without open surgical wounds and unnecessary deformation or destruction of the mucosal structure.

[Histological study on the effects of ethanol injection on mouth mucosa contraction loss].

We previously reported that a loss of contraction in the mucosal tissue of the palate arch is effectively induced by ethanol injections of moderate concentration and dosage. The present study was performed to obtain more information on how such ethanol injections induce contraction loss in mucosa tissue. Guinea pigs of both sexes were used in this study. The left arch of the palate mucosa was injected with 2 microliters of 70% ethanol and used as the experimental group. The right arch of the palate mucosa of the same animal was injected with saline and used as a control. One, three, five, eight, 10, 30, 50, and 90 days after injection, the mucosal tissues that received the injection were resected under anesthesia and processed for light microscopy using standard procedures. One day after the ethanol injection, severe coagulative degeneration of the mucosal tissue of the palate was seen. However, the damaged area was strictly restricted to the arch of the palate. Coagulative degeneration of the tissue peaked three days after the injection. Thereafter, the mucosal epithelial and mucosal connective tissues regenerated, and the damaged mucosal tissue quickly began to repair. An apparent cicatricial contraction loss was observed 10 days after the ethanol injection, along with the progression of fibrotic changes in the submucosal connective tissue of the arch of the palate. The regenerative action of the mucosal arch of the palate abated 30 days after the ethanol injection, and the reduced mucosal tissue appeared to have become denser as a result of an increase in dense fibrous connective tissue in the submucosal layer. No cell malignancies were seen throughout the entire 90-day observation period. In conclusion, cicatricial contraction loss of the mucosal arch of the palate resulting from the injection of an appropriate concentration and dosage of ethanol leads to the regeneration of the mucosal epithelium and fibrotic changes in the submucosa. The ethanol injection described here seems to be extremely safe, since it exerted no malignant effects on the cells and tissues either morphologically or functionally.

[Experimental study of contraction loss effects of mouth mucosa by ethanol injection].

We began treating patients with simple snoring and obstructive sleep apnea syndrome (OSAS) with the coblator radiofrequency generator in our outpatient clinic from April 2001. Good clinical results have been obtained, but we noticed a contractile effect on mucosa from ethanol, which possesses marked sclerotic degenerative action on tissue as well as radiofrequency energy. We conducted a series of experiments in a guinea pig model to investigate the efficacy of local ethanol injection in contracting mouth mucosa. To examine the influence on respiration of liquid injection, physiological saline was gradually injected in decrements into the arch of the palate mucosa. We found that the safe dosage that did not bring about edema and subsequent dyspnea was under 10 microliters. Based on this finding, ethanol in concentrations of 50%, 70%, and 100% at volumes of 1, 2, 4, 8, and 10 microliters was injected into the arch of the palate mucosa in guinea pigs and changes in local field mucosa were observed daily. In the 50% ethanol injection, no clear contractile effect on mucosa could be observed at any dosage. In contrast, the 100% ethanol injection led to strong tissue impairment that caused extensive necrotic collapse of the local field mucosa, even when the dosage was down to the minimum of 1 microliter. We found that, injection of 70% ethanol at 1 or 2 microliters, however, resulted in formation of a local field mucosa wound of lesser degree that healed completely within a few days, associated with moderate contraction of mucosal tissue. We concluded that in moderate dosage, 70% ethanol seems to have the potential for the treatment of endermosis, such as uvuloptosia (elongated uvula) and hypertrophy of palate mucosa, as a useful mucosa contractile agent.