Similarities and Differences Between "Proactive" and "Passive" Stress-Coping Rats in Responses to Sucrose, NaCl, Citric Acid, and Quinine

Abstract

A stress-coping style describes a set of behavioral and physiological measures that characterize an individual's response to stressful stimuli. It would follow that different stress-coping styles are associated with differential sensitivity for taste stimuli. Animals with stress-coping characteristics better suited to an environment in which new foods are more frequently encountered may show enhanced orosensitivity to cues that signal toxins and/or nutritional value. Here, rats were categorized as "proactive" or "passive" based on results from a defensive burying test. Next, the brief-access taste procedure was used to compare unconditioned licking responses to a concentration array of compounds that humans describe as "sweet" (sucrose), "salty" (NaCl), "sour" (citric acid), and "bitter" (quinine) across the 2 groups. Both groups displayed concentration-dependent lick responses to sucrose, NaCl, citric acid, and quinine. The passive group initiated significantly fewer trials to sucrose than the proactive rats, but the groups did not significantly differ in trial initiation for the other 3 test compounds. Thus, differences in food intake, body weight, and glucose homeostasis between the stress-coping styles are not likely driven by alterations in orosensory responsivity. However, the current findings lend support to the hypothesis that the 2 groups differ in reward-related signaling mechanisms.

Development of a model for robust and exploratory analysis of the rodent brief-access taste aversion data

“…Data from BATA experiments are generally displayed by concentration-response curves representing the means of the number of licks or "lick ratios" as a function of the concentrations of the compound tested and the standard error (SE) or standard deviation (SD) obtained with a number n of rats (3,5,7,8,11,12,(15)(16)(17)(18). This way of presenting the results can…”

Impact of Calorie-Restricted Cafeteria Diet and Treadmill Exercise on Sweet Taste in Diet-Induced Obese Female and Male Rats

“…In the preference test, a reduction in sucrose intake can be interpreted as anhedonia and decreased appetitive behavior [ 61 ]. Similarly, in the taste reactivity test and the brief-access test, the number of animals initiating the behavior and the number of trials initiated, respectively, can also be interpreted as a measure of appetitive behavior [ 49 ]. In the taste reactivity test, the hedonic reactions elicited by the tasting of sucrose are considered a measure of how much the animals liked the stimulus [ 40 , 46 ], and a similar interpretation can be made from the preference index in the preference test [ 40 ].…”

“…In the taste reactivity test, the hedonic reactions elicited by the tasting of sucrose are considered a measure of how much the animals liked the stimulus [ 40 , 46 ], and a similar interpretation can be made from the preference index in the preference test [ 40 ]. Lastly, in the brief-access test, the lick responses at each sucrose concentration can be interpreted as a measure of the ingestive or consummatory behavior elicited by the tastant [ 47 , 48 , 49 ]. The length of the licking episodes performed at each sucrose concentration is a measure of the orosensory feedback power and the perceived palatability of that sucrose concentration [ 52 , 62 ].…”

“…Mean lick scores data for each group were curve fitted using the following logistic function [ 49 , 50 ]: where a is the asymptotic lick response, b is the lower lick response, x is the log 10 stimulus concentration, c is the log 10 concentration at the inflection point, and d is the slope of the curve.…”

Experimental protocol for detecting higher alcohol consumers from a conventional rat line based on basal anxiety

“…It is based on the observation of spontaneous activity of rodents when they are placed in a novel and aversive environment produced by the height, lighting, and open spaces. In rat populations, proactive coping behavior is distributed in a U-shaped curve, meaning that only a small portion of the population will display an intermediate coping style and the remaining individuals are characterized as either clearly proactive or clearly passive coping [ 12 , 15 ]. The EPM consisted of two open arms (50 × 10 cm) and two enclosed arms (50 × 10 × 50 cm), raised 50 cm from the floor, located in a room with a dim white light.…”