Complementary interactions between command-like interneurons that function to activate and specify motor programs.

Motor activity is often initiated by a population of command-like interneurons. Command-like interneurons that reliably drive programs have received the most attention, so little is known about how less reliable command-like interneurons may contribute to program generation. We study two electrically coupled interneurons, cerebral-buccal interneuron-2 (CBI-2) and CBI-11, which activate feeding motor programs in the mollusk Aplysia californica. Earlier work indicated that, in rested preparations, CBI-2, a powerful activator of programs, can trigger ingestive and egestive programs. CBI-2 reliably generated ingestive patterns only when it was repeatedly stimulated. The ability of CBI-2 to trigger motor activity has been attributed to the two program-promoting peptides it contains, FCAP and CP2. Here, we show that CBI-11 differs from CBI-2 in that it contains FCAP but not CP2. Furthermore, it is weak in its ability to drive programs. On its own, CBI-11 is therefore less effective as a program activator. When it is successful, however, CBI-11 is an effective specifier of motor activity; that is, it drives mostly ingestive programs. Importantly, we found that CBI-2 and CBI-11 complement each other's actions. First, prestimulation of CBI-2 enhanced the ability of CBI-11 to drive programs. This effect appears to be partly mediated by CP2. Second, coactivation of CBI-11 with CBI-2 makes CBI-2 programs immediately ingestive. This effect may be mediated by specific actions that CBI-11 exerts on pattern-generating interneurons. Therefore, different classes of command-like neurons in a motor network may make distinct, but potentially complementary, contributions as either activators or specifiers of motor activity.

Effect of swallowing exercises in independent elderly.

The aim of this study was to investigate the effects of swallowing exercises on oral function in independent elderly patients visiting the Department of Prosthodontics at Tokyo Dental College Chiba Hospital. Twenty-nine patients aged over 65 years (15 men and 14 women; mean age, 75.0 years) in whom treatment was completed at this college were enrolled in the study. The patients were instructed on how to perform swallowing exercises monthly (including at baseline) for the first 2 months from the start of the study and asked to perform those exercises at least once daily. At the beginning and end of the study (a 3-month study period), the Repetitive Saliva Swallowing Test was conducted and occlusal force, oral diadochokinesis, unstimulated whole saliva flow rate, stimulated whole saliva flow rate, salivary pH at rest, and salivary buffering capacity measured to determine the effects of the exercises on oral function. Analyses demonstrated significant increases in diadochokinesis rate (/ta/ and /ka/) and unstimulated whole saliva flow rate (p<0.05), suggesting that the swallowing exercises promote the maintenance and improvement of oral function in the independent elderly.

Reversal of soft-tissue anesthesia in asymptomatic endodontic patients: a preliminary, prospective, randomized, single-blind study.

INTRODUCTION: Phentolamine has been reported to be an effective local anesthetic reversal agent for soft tissue but has not been studied in endodontics. The purpose of this preliminary, prospective, randomized, single-blind study was to evaluate the reversal of soft-tissue anesthesia using phentolamine in asymptomatic endodontic patients. METHODS: Eighty-five adult subjects having a maxillary or mandibular asymptomatic tooth requiring endodontic therapy received either phentolamine or sham treatment(s) at the end of the endodontic treatment appointment. Soft-tissue anesthesia was monitored by subjects every 15 minutes for 5 hours. Subjects reported postoperative injection site pain and tooth pain using a Heft-Parker visual analog score every 30 minutes for the first 2 postoperative hours and every hour for 3 hours. RESULTS: There was a statistically significant difference in time to return-to-normal sensation for the maxillary lip/cheek and mandibular lip. Subjects who received phentolamine experienced an 88-minute decrease in time to return-to-normal maxillary lip/cheek sensation and a 47-minute decrease in time to return-to-normal mandibular lip sensation. The administration of phentolamine was not significantly more painful than administration of a sham treatment, and patients who received phentolamine did not experience significantly more postoperative pain at the injection site. Postoperative complications were minimal, and no clinically significant adverse reactions to the phentolamine were reported. CONCLUSIONS: Phentolamine would be beneficial for asymptomatic endodontic patients who would like to experience a faster return-to-normal soft-tissue function and sensation after the administration of local anesthesia.

Altering the gag reflex via a palm pressure point.

BACKGROUND: The gag reflex regularly interferes with dental procedures. The authors hypothesize that applying pressure to a specific point on the palm alters the gag reflex and that hypersensitive gag reflexes may be categorized according to oropharyngeal landmarks. METHODS: Thirty-six neurologically intact subjects underwent a series of gag reflex trials (baseline, sham and treatment). The authors developed a hand pressure device for subjects to wear, which provided a consistent force, and they described a gag trigger point index (GTPI) scale. On the basis of the GTPI, they divided subjects into a hypersensitive group and an expected-sensitivity (control) group. RESULTS: The trigger point of the gag reflex moved posteriorly in all subjects as a result of pressure to the palm point. Statistical results from repeated measures analysis of variance support the GTPI baseline data, and group assignments helped predict mean GTPI scores across conditions. The authors noted a significant treatment-group interaction effect, which indicated that the difference in mean GTPI responses between the hypersensitive and expected-sensitivity groups depended on the treatment being used. CONCLUSIONS: The authors introduce a treatment involving the stimulation of a pressure point that consistently altered the gag reflex trigger. The results of the study show the need for a more detailed, systematic approach to studying the hypersensitive gag reflex. CLINICAL IMPLICATIONS: The change in trigger point in the hypersensitive group represented a functional gain. Application of the pressure point during dental procedures would decrease the likelihood of triggering a gag reflex.

In vitro permeation through porcine buccal mucosa of Salvia desoleana Atzei & Picci essential oil from topical formulations.

In the light of recent studies, which have shown that the essential oil derived from some Lamiaceae species has appreciable anti-inflammatory activity, moderate anti-microbial action and the ability to inhibit induced hyperalgesia, an assessment of the diffusion and permeation of Salvia desoleana Atzei & Picci (S. desoleana) essential oil through porcine buccal mucosa was considered useful for a possible application in the stomatological field. Topical formulations (microemulsions, hydrogels and microemulsion-hydrogels) were prepared for application to the buccal mucosa. The mucosa permeation of the oil from the formulations was evaluated using Franz cells, with porcine buccal mucosa as septum between the formulations (donor compartment) and the receptor phase chambers. The study also aimed at optimising the permeability of the S. desoleana essential oil by means of an enhancer, the diethylene glycol monoethyl ether Transcutol. The diffusion of the oil through the membrane was determined by evaluating the amount of essential oil components present in the receiving solution, the flux and the permeation coefficient (at the steady state) in the different formulations at set intervals. Qualitative and quantitative determinations were done by gas chromatographic analysis. All the formulations allow a high permeability coefficient in comparison with the pure essential oil. In particular, the components with a terpenic structure (beta-pinene, cineole, alpha-terpineol and linalool) have the highest capacity to pass through the porcine buccal mucosa when compared to the other components (linalyl acetate and alpha-terpinil acetate). Moreover, the enhancer, diethylene glycol monoethyl ether largely increases the permeation of the essential oil components in relation to the concentration.

Relationship between dietary, serum, and tissue levels of carotenoids.

A study was undertaken to assess the utility of the buccal scrape technique for measuring tissue levels of carotenoids in short-term intervention trials and epidemiologic studies. In 14 healthy volunteers a good correlation was found between serum beta-carotene levels and recent dietary intake of beta-carotene as estimated from measured food records. Supplementation with 30 mg/day of beta-carotene for 1 week resulted in a sixfold increase in average serum levels, while serum lycopene concentrations remained constant. Presupplementation levels of beta-carotene and lycopene in the buccal mucosa cells were not correlated with dietary intakes or with serum levels. After supplementation, levels of both carotenoids were found to increase in buccal cells, however, most of this increase was found to be an artifact due to repeated sampling. After correcting for this artifact, beta-carotene was found to increase less than twofold in tissue after supplementation.