Multiple processes underlie benzodiazepine-mediated increases in the consumption of accepted and avoided stimuli.

Hyperphagia is a reported side effect of anxiolytic benzodiazepines such as chlordiazepoxide (CDP). Prior research has focused primarily on the ingestive responses to sweet or solid foods. We examined CDP effects on licking for normally accepted and avoided taste solutions across a range of concentrations. The effect of CDP (10 mg/kg) versus saline on the licking patterns of water-restricted rats for water and 3 concentrations of sucrose, saccharin, NaCl, monosodium glutamate (MSG), citric acid, and quinine (Q-HCl) solutions was evaluated during 1 h tests. CDP increased meal size for all tastants except citric acid. Analysis of licking microstructure revealed 3 dissociable effects of CDP. CDP affected oromotor coordination as indicated by a uniform increase in the modal interlick interval for all stimuli. CDP increased meal size as indicated by shorter pauses during consumption of water, MSG, and weaker saccharin concentrations, and by fewer long interlick intervals (250-2000 ms) for normally avoided tastants. CDP also increased meal size by increasing burst size, burst duration, and the initial rate of licking for most solutions, suggesting increased hedonic taste evaluation. CDP did not affect variables associated with postingestive feedback such as meal duration or number of bursts, and the results also suggest that CDP did not enhance the perceived taste intensity. We hypothesize that the reduction of pause duration is consistent with an increased motivation to sample the stimulus that synergizes with changes in taste-mediated responsiveness to some but not all stimuli to yield increases in the consumption of both normally accepted and avoided taste stimuli.

Cost-free and sustainable incentive increases healthy eating decisions during elementary school lunch.

We aimed to develop a cost-free and sustainable program to influence healthier eating decisions during elementary school lunch. Baseline food and beverage choices were assessed for 9 days during lunch service at two racially and economically diverse elementary schools in Spartanburg County, SC, USA. After being informed that the labeled items on the daily lunch menu represented the healthiest choice, students were allowed to ring a call bell in the cafeteria for public recognition when they chose all of the identified healthiest food and beverage items during lunch service. Using menus matched to the baseline phase, food and beverage choices were measured during a 9-day intervention phase. After 30 days, food and beverage choices were reassessed during a 3-day follow-up phase. Healthiest food & beverage choices increased 49% with >60% of students choosing non-flavored milk over flavored milk during the intervention phase. There was no difference in the success of the program between the two schools. The program continued and healthy eating decisions were significantly sustained at a 30-day follow-up assessment. Public recognition through bell ringing appears to be an effective practice to sustain increases in healthy eating decisions during elementary school lunch and warrants expansion to larger scale, longitudinal trials.

Responses of single lingual nerve fibers to thermal and chemical stimulation.

The goals of this study were to characterize the responses of: (1) thermally-sensitive fibers of the lingual branch of the trigeminal nerve to cooling from 35 degrees to 10 degrees C at a rate of 1 degrees C/s; and (2) these neurons to a mid-range concentration of NaCl (150 mM), glucose (150 mM), citric acid (0.3 mM), and quinine-HCl (3 mM) at 35 degrees and 25 degrees C. A cluster analysis of 47 neurons' responses to cooling revealed two major groups and one minor group. Group 1 neurons (n=19) had a shorter latency, exhibited faster time-to-peak activity, and responded over a smaller range of temperature compared to Group 2 neurons (n=22). Group 3 neurons (n=6) exhibited the longest response latency and responded over a wider cooler range of temperature. Twenty-five out of thirty-one thermally-sensitive, non-tactile lingual neurons responded weakly to at least one chemical stimulus, with some neurons responding to 2, 3, or all 4 chemical stimuli. Group 1 neurons responded to more chemical stimuli at 35 degrees C, while Group 2 neurons responded more at 25 degrees C. Under their optimal temperature conditions, Group 1 and Group 2 neurons responded most often to citric acid and least often to glucose, with NaCl and Q-HCl eliciting an intermediate number of responses. As a whole, the responses of thermally-sensitive fibers to chemical stimulation were modest at best with an absence of chemical specificity. There was no evidence of a 'best' stimulus, although there was a suggestion of temporal coding.

Magnetic field conditioned taste aversion in rats.

Conditioned taste aversion is a common classic conditioning procedure used to identify noxious stimuli. When a rat is given a taste solution, the conditioned stimulus (CS), followed by an unpleasant experience, the unconditioned stimulus (US), the rat will avoid consumption of the CS in future presentations. These experiments use the taste aversion procedure to examine the effect of exposure to a high magnetic field. A solution consisting of 3.0 g glucose and 1.25 g saccharin per 1 L of solution (G+S) was used as the CS and a 9.4-T magnet served as the US. In Experiment 1, all rats received a 10 min presentation of the G+S solution followed by either a 30 min exposure to the magnetic field (Magnet, n = 8), a 30-min exposure in a container with similar conditions but lacking the magnetic field (Sham, n = 8), or no exposure (Control, n = 8). The Magnet Group showed a taste aversion on the first day of preference testing (p < 0.05). Experiment 2 employed the same US-CS protocol for 3 consecutive days of conditioning. The Magnet Group demonstrated a taste aversion for the postexposure Days 1-8 (p < 0.01). There was no difference between the Sham and Control Groups in either experiment. The results of this study clearly demonstrate that the rats associated the G+S solution with the experience of being exposed to the high magnetic field and avoided the solution in subsequent presentations.

Role for epithelial Na+ channels and putative Na+/H+ exchangers in salt taste transduction in rats.

The effects of the epithelial Na+ channel antagonists amiloride and benzamil and the Na+/H+ exchange antagonist 5-(N,N-dimethyl)-amiloride (DMA)-Cl on the integrated responses of the chorda tympani nerve to 30, 75, 150, 300, and 500 mM concentrations of NaCl, KCl, and NH4Cl were assessed in male Sprague-Dawley rats. Based on evidence from other systems, 1 and 25 microM amiloride and benzamil were chosen to selectively inhibit epithelial Na+ channels and 1 microM DMA was chosen to selectively inhibit Na+/H+ exchange. When added to stimulating salt solutions, amiloride, benzamil, and DMA were each effective in inhibiting responses to all three salts. The degree of inhibition varied with drug, salt, and salt concentration, but not drug dose. Amiloride suppressed NaCl responses to a greater degree than KCl and NH4Cl responses, whereas DMA suppressed NH4Cl responses to a greater degree than NaCl and KCl responses. In all but one case (25 microM amiloride added to KCl), drug suppression of taste nerve responses decreased with an increase in salt concentration. The present results suggest that 1) epithelial Na+ channels in rat taste receptor cells may play a role in KCl and NH4Cl taste transduction; 2) a Na+/H+ exchange protein may be present in taste receptor cells, representing a putative component, in addition to epithelial Na+ channels, in salt taste transduction; and 3) salt taste detection and transduction may depend on the utilization of a combination of common and distinct transcellular pathways.