Ice cube stimulation helps to improve dysgeusia.

Dysgeusia causes a decrease in appetite, and it is one of the major factors in undernutrition. Dysgeusia is elicited by numerous causes, and in many cases it is still difficult to treat the various symptoms complained of by patients. We herein report a case in which dysgeusia was improved by transient cooling of the mouth.

Effects of midazolam on acquisition and extinction of conditioned taste aversion memory in rats.

Some intravenous anesthetic agents such as midazolam are known to induce anterograde and retrograde amnesia. We analyzed the effect of midazolam by the conditioned taste aversion (CTA) acquisition and retention. After the rats were offered 0.1% sodium saccharin (Sac) as conditioned stimulus (CS), an intraperitoneal (i.p.) injection of several concentrations (5-30mg/kg) of midazolam was followed by an i.p. injection of 0.15M LiCl (2% of body weight) as unconditioned stimulus (US). The rats, which acquired CTA by every CS-US paradigm, strongly avoided Sac on the 1st test day after conditioning and maintained the avoidance for 3 days. We have already reported that Sac intake abruptly increased on the 2nd test day and the almost complete extinction occurred on the 3rd test day after conditioning by injection of subhypnotic dose of propofol before LiCl-injection. In contrast, we found that subhypnotic dose of midazolam suppressed not only CTA acquisition, but also CTA retention. On the other hand, an alpha2-adrenergic blocker, yohimbin (1mg/kg) suppressed only the CTA retention. These results suggest that the subhypnotic doses of midazolam firstly affect the acquisition mechanism of the CTA memory (CTAM), resulting the suppression of the retention of CTAM.

Management of exaggerated gag reflex using intravenous sedation in prosthodontic treatment.

The gag reflex is a somatic natural response in which the body attempts to eliminate instruments or agents from the oral cavity by muscle contraction. Some patients suffered from such severe retching that behavioral techniques did not sufficiently reduce gagging in dentistry. In these patients, pharmacological management was thought to be the last alternative to eliminate the reflex. However, the potential of intravenous (IV) sedation as a way to overcome problems in gagging management during prosthodontic (prosthetic) therapy has not been sufficiently explored. We examined the benefit of IV sedation to facilitate prosthodontic treatment for problematic gagging patients intolerable to dental therapy. The subjects were 10 severely retching patients (7 males and 3 females) who received prosthodontic or restorative therapy under propofol IV sedation. The number, location and prognosis of dentures/restorations were reviewed retrospectively. Eight dentures (3 removable and 5 fixed partial dentures) and 22 restorations (18 crowns and 4 inlays) were seated successfully in the oral cavity without serious complications related to IV sedation. The restored teeth were located predominantly in the posterior regions. Throughout the observation period of at least 6 months, no symptoms of postoperative pain or swelling were found. Five of the 10 patients showed improved tolerance to oral inspection, indicating a behavioral adjustment to dental care. In prosthodontic treatment extended to the posterior regions, propofol IV sedation proved useful in managing reflex control.

Subhypnotic doses of propofol accelerate extinction of conditioned taste aversion.

Subhypnotic doses of propofol accelerate extinction of conditioned taste aversion. Some intravenous anesthetic agents including propofol is known to induce anterograde and retrograde amnesia. We evaluated whether propofol affect the long-term memory formed by the conditioned taste aversion (CTA) paradigm. Rats were allowed a 4h access to water through the experiments. After preconditioning water intake, the rats were offered 0.1% sodium saccharin (Sac) as conditioned stimulus (CS) for 20 min. An intraperitoneal (i.p.) injection of several concentrations (0.5-100 mg/kg) of propofol 10 min after Sac exposure was followed by an i.p. injection of 0.15M LiCl (2% of body weight) as unconditioned stimulus (US) 30 min after CS-exposure. The volumes of intake of Sac for 20 min were measured on the successive 4 days. The rats, which acquired CTA by every CS-US paradigm, strongly avoided Sac on the first test day after conditioning and maintained the avoidance for 3 days. However, when subhypnotic dose of propofol was injected before LiCl-injection, Sac intake abruptly increased on the second test day and the almost complete extinction occurred on the third test day after conditioning. The extinction process of CTA was barely affected by hypnotic dose of propofol. These results suggest that propofol affects the retention mechanism of the CTA memory in a dose-dependent manner. Subhypnotic dose of propofol may affect the sub-cellular process of the memory consolidation in CTA.