Expression profile of the zinc transporter ZnT3 in taste cells of rat circumvallate papillae and its role in zinc release, a potential mechanism for taste stimulation.

Zinc is an essential trace element, and its deficiency causes taste dysfunction. Zinc accumulates in zinc transporter (ZnT)3-expressing presynaptic vesicles in hippocampal neurons and acts as a neurotransmitter in the central nervous system. However, the distribution of zinc and its role as a signal transmitter in taste buds remain unknown. Therefore, we examined the distribution of zinc and expression profiles of ZnT3 in taste cells and evaluated zinc release from isolated taste cells upon taste stimuli. Taste cells with a spindle or pyriform morphology were revealed by staining with the fluorescent zinc dye ZnAF-2DA and autometallography in the taste buds of rat circumvallate papillae. Znt3 mRNA levels were detected in isolated taste buds. ZnT3-immunoreactivity was found in phospholipase-ß2-immunopositive type II taste cells and aromatic amino acid decarboxylase-immunopositive type III cells but not in nucleoside triphosphate diphosphohydrolase 2-immunopositive type I cells. Moreover, we examined zinc release from taste cells using human transient receptor potential A1-overexpressing HEK293 as zinc-sensor cells. These cells exhibited a clear response to isolated taste cells exposed to taste stimuli. However, pretreatment with magnesium-ethylenediaminetetraacetic acid, an extracellular zinc chelator - but not with zinc-ethylenediaminetetraacetic acid, used as a negative control - significantly decreased the response ratio of zinc-sensor cells. These findings suggest that taste cells release zinc to the intercellular area in response to taste stimuli and that zinc may affect signaling within taste buds.

Effectiveness of pharmacist intervention for deprescribing potentially inappropriate medications: a prospective observational study.

BACKGROUND: Potentially inappropriate medications (PIMs) and polypharmacy in older adults lead to increase the risk of adverse drug events. This study aimed to evaluate the effectiveness of pharmacist intervention combining the criteria for detecting PIMs with the deprescribing algorithm on correcting PIMs, reducing the number of medications, and readmissions. METHODS: A prospective observational study was conducted at a Japanese University Hospital enrolling new inpatients aged ≥65 years prescribed ≥1 daily medication. Pharmacists detected PIMs based on the criteria combined the screening tool of older persons' potentially inappropriate prescriptions criteria version 2 with the screening tool for older persons' appropriate prescriptions for Japanese, examined changes using the deprescribing algorithm, and suggested changes to the physician. The proportion of patients whose number of medications was reduced at discharge and the rate of readmissions within 30 and 90 days were compared between patients without PIMs (without PIMs group), patients who were not suggested to change PIMs (no suggestions group), and patients who were suggested to change PIMs (suggested group). RESULTS: The study enrolled 544 patients (median age 75.0 years, 54.4% males, median number of medications 6.0/patient). The number of patients with PIMs was 240 (44.1%), and 304 patients had no PIMs (without PIMs group). Among the patients with PIMs, 125 (52.1%) patients received pharmacist suggestions to change ≥1 PIMs (suggested group), and 115 patients received no suggestions for change (no suggestions group). The total number of PIMs was 432, of which changes were suggested for 189 (43.8%). Of these 189 cases, 172 (91.0%) were changed. The proportion of patients whose number of medications was reduced was significantly higher in the suggested group than in the without PIMs group and the no suggestions group [56.8% (71/125) vs. 26.6% (81/304) and 19.1% (22/115), respectively; P < 0.001 in both comparisons]. There were no significant differences in the rates of readmissions within 30 and 90 days among the three groups. CONCLUSIONS: Pharmacist intervention combining the criteria for detecting PIMs with the deprescribing algorithm was effective for correcting PIMs and may be associated with a reduction in the number of medications.

Oxaliplatin Alters Expression of T1R2 Receptor and Sensitivity to Sweet Taste in Rats.

As one of the adverse effects of oxaliplatin, a key agent in colon cancer chemotherapy, a taste disorder is a severe issue in a clinical situation because it decreases the quality of life of patients. However, there is little information on the mechanism underlying the oxaliplatin-induced taste disorder. Here, we examined the molecular and behavioral characteristics of the oxaliplatin-induced taste disorder in rats. Oxaliplatin (4-16 mg/kg) was administered to Sprague-Dawley (SD) rats intraperitoneally for 2 d. Expression levels of mRNA and protein of taste receptors in circumvallate papillae (CP) were measured by real-time quantitative polymerase chain reaction (PCR) and immunohistochemistry, respectively. Taste sensitivity was assessed by their behavioral change using a brief-access test. Morphological change of the taste buds in CP was evaluated by hematoxyline-eosin (HE) staining, and the number of taste cells in taste buds was counted by immunohistochemical analysis. Among taste receptors, the expression levels of mRNA and protein of T1R2, a sweet taste receptor subunit, were increased transiently in CP of oxaliplatin-administered rats on day 7. In a brief-access test, the lick ratio was decreased in oxaliplatin-administered rats on day 7 and the alteration was recovered to the control level on day 14. There was no detectable alteration in the morphology of taste buds, number of taste cells or plasma zinc level in oxaliplatin-administered rats. These results suggest that decreased sensitivity to sweet taste in oxaliplatin-administered rats is due, at least in part, to increased expression of T1R2, while these alterations are reversible.