Total Number Of Licks Research Articles

Reduced menthol sensitivity in a prodromal Parkinson's disease model induced by intranasal rotenone treatment.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor symptoms, and it is associated with several prodromal non-motor symptoms, including an impaired sense of smell, taste and touch. We previously reported that bitter taste impairments occur independently of olfactory impairments in an early-stage PD animal model using short-term intranasal rotenone-treated mice. Cool temperatures also affect bitter taste perception, but it remains unclear whether or not bitter taste impairments result from an altered sensitivity for intraoral cool stimuli. We examined disturbances in the intraoral menthol sensitivity, such as coolness at low concentrations of menthol, using a brief-access test. Once a day, one solution from the 7-concentration series of (-)-menthol (0-2.3 mM) or the bitter taste quinine-HCl (0.3 mM) was randomly presented 20 times for 10 s to water-deprived mice before and 1 week after rotenone treatment. The total number of licks within 20 times was significantly decreased with the presentation of 2.3 mM menthol and quinine-HCl, compared to distilled water in untreated mice, but not in rotenone-treated mice. The correlation between the licks for quinine-HCl and that for menthol was increased after rotenone treatment. In contrast, the 2-bottle choice test for 48 h clarified that menthol sensitivity was increased after rotenone treatment. Furthermore, a thermal place preference test revealed that seeking behavior toward a cold-floored room was increased in the rotenone-treated mice despite the unchanged plantar cutaneous cold sensitivity. These results suggest that taste impairments in this model mice are at least partly due to intraoral somatosensory impairments, accompanied by peripheral/central malfunction.

Taste Preference Between Ruminant and Industrial Trans Fat in C57BL/6 Mice Measured With the Automated IntelliCage System

ObjectivesThe objective is to evaluate the taste preference between water, lecithin, R-TFA and I-TFA (TFAs in lecithin at a ratio of 14:86 (w/w)) nanovesicles measured with the automated IntelliCage system in C57BL/6 mice. We hypothesized that the preference for industrially originated trans-fatty acids (elaidic acid (EA trans 18: 1n-9)) and ruminant trans fatty acids (trans-palmitoleic acid (TPA t16:1 n-7)) -is higher than lecithin (control) and/or water. The objective is to evaluate the taste preference between water, lecithin, R-TFA and I-TFA (TFAs in lecithin at a ratio of 14:86 (w/w)) nanovesicles measured with the automated IntelliCage system in C57BL/6 mice.MethodsTwenty-four female C57BL/6 mice were divided into 2 groups in two separate IntelliCages where had ad libitum access to food (Teklad global 18% protein extruded (18% fat)). On week 1, both groups had access to only water (control). On week 2, in cage 1 mice received lecithin and EA and in cage 2 mice received lecithin and TPA. In week 3 mice had access to only water. On weeks 4 and 5, mice had access to EA and TPA where the positions of trans fatty acids were interchanged for week 5 compared to week 4. Water also was added to the cages on week 5. Mice weights were measured for each week. Corner preference was recorded by 1- the number of the times a mouse enters a corner (corners visits), 2- crossing a hole to reach the bottles (nose pokes); and 3-the number of licking the bottles (licks). Differences between total number of licks was assessed by t-test.ResultsDuring week 2, mice preferred either EA (7.6 times) in cage 1 or TPA (7.9 times) in cage 2 over lecithin (P < 0.05). During week 4 in cage 1, the mice drank more EA (3.14 times) compared to TPA (P < 0.05). Oppositely during week 4, in cage 2, mice drank more TPA compared to EA (1,2 times, P < 0.05). After corners were switched for fat solutions in week 5, mice drank TPA 2.66 times more than EA (P < 0.05) and 3.5 times more than water (P < 0.05) in cage 1. Equally in cage 2, mice drank EA 1.44 and 4.4 times more than TPA and water (P < 0.05) in week 5.ConclusionsResults showed mice preferred dietary trans fat, either EA and TPA in equal matter over control and drinking water. Further, mice changed their fat preference (EA to TPA and TPA to EA) when the positions of trans fatty acids in corners were switched; therefore, more analysis needs to be done.Funding SourcesNSERC, CMDO.

Non‐random distribution of ungulate salt licks relative to distance from North American oceanic margins

AbstractAimTerrestrial deposition of aerosol marine sodium declines with distance from coastlines. Salt deprivation in vertebrate herbivores and salt‐seeking behaviours should hence increase with distance inland. We analyse published geospatial data on ungulate‐patronized salt licks to test whether they are non‐randomly distributed relative to distance from oceans and elevation.LocationCanada, Alaska and the contiguous United States.TaxonCetartiodactyla (even‐toed ungulates).MethodsWe determined the land area and median elevation of 100 km increments from the North American coast. The null model of the expected number of licks within each interval was determined by the ratio of the interval's land area to the total land area, multiplied by the total number of licks. We asked whether the number of licks further from coastlines was significantly higher than chance. We also assessed whether licks occur disproportionately at higher elevations, comparing the median elevation of observed licks to the median elevation within each interval.ResultsWe found a strong positive relationship between salt lick patronage by ungulates and distance from the coast. Licks occurred significantly less often within, and more often beyond, 500 km inland, and at significantly higher elevations than would be expected by chance.Main conclusionsThese findings indicate that the patronage of salt licks is constrained geographically, and that the foraging behaviour of ungulates and other phytophagous vertebrate taxa may be influenced over large spatial scales by sodium availability. Salt‐seeking behaviour varies on a wide biogeographical scale across North America, with concomitant implications for vertebrate herbivore behaviour and ecology.

Projections from the nucleus accumbens shell to the ventral pallidum are involved in the control of sucrose intake in adult female rats.

In rodents, stimulation of the nucleus accumbens shell (AcbSh) directly or via its projection to the lateral hypothalamus (LH) attenuates food intake. The ventral pallidum (VP) receives dense projections from the AcbSh and is sensitive to the hedonic aspect of food and motivation for reward. However, the role of accumbal projections to the VP in the regulation of food intake was not well investigated. In the present study conducted on female rats, we examined the effects of stimulation of the AcbSh using optogenetics, or pharmacological inhibition of the rostral VP, or stimulation of projections from the AcbSh to the rostral VP using optogenetics on the consumption of 10% sucrose, lick microstructure and the expression of c-fos mRNA. Stimulation of the AcbSh, inhibition of the rostral VP with muscimol, or stimulation of axonal terminals from the AcbSh to the rostral VP resulted in a decrease in sucrose intake, meal duration, and total number of licks. The licking microstructure analysis showed that optogenetic stimulation of AcbSh or axonal terminals from the AcbSh to the rostral VP decreased the hedonic value of the sucrose. However, inhibition of the rostral VP decreased the motivation, whereas stimulation of the accumbal projections in the rostral VP increased the motivation to drink. This difference could be due to differential involvement of GABAergic and glutamatergic VP neurons. Stimulation of the AcbSh resulted in a decrease of c-fos mRNA expression in the LH and rostral VP, and stimulation of axonal terminals from the AcbSh to the rostral VP decreased c-fos mRNA expression only in the rostral VP. This study demonstrates that in adult female rats, in addition to the already known role of the AcbSh projections to the LH, AcbSh projections to the VP play a major role in the regulation of sucrose intake.

"Contexts control negative contrast and restrict the expression of flavor preference conditioning": Correction to Austen and Sanderson (2016).

Reports an error in "Contexts control negative contrast and restrict the expression of flavor preference conditioning" by Joseph M. Austen and David J. Sanderson (Journal of Experimental Psychology: Animal Learning and Cognition, 2016[Jan], Vol 42[1], 95-105). In Table 2 of the article, the conditions in Experiment 3 are labeled AB and XY, but they should be AX and BY. (The following abstract of the original article appeared in record 2015-59080-002.) Consumption of a high concentration of sucrose can have either a detrimental, negative contrast effect or a facilitatory, preference conditioning effect on subsequent consumption of a low concentration of sucrose, depending on the cues that are present during consumption. The role of context and flavor cues in determining these effects were studied using analysis of the microstructure of licking in mice. Exposure to a high concentration followed by exposure to a low concentration resulted in a transient reduction in mean lick cluster size, which was context dependent (Experiment 1). However, there was no change in the total number of licks or overall consumption. When a flavor that had previously been paired with a high concentration was paired with a low concentration, there was an increase in the total number of licks, and overall consumption, but no change in the mean lick cluster size (Experiment 2). Pairing a high concentration with a flavor in a particular context before pairing the context and flavor compound with a low concentration resulted in abolishing the expression of the flavor preference conditioning effect on the total number of licks and consumption (Experiment 3). These results demonstrate that although context and flavor cues have dissociable effects on licking behavior, their interaction has an antagonistic effect on the behavioral expression of memory. (PsycINFO Database Record

Contexts control negative contrast and restrict the expression of flavor preference conditioning.

Consumption of a high concentration of sucrose can have either a detrimental, negative contrast effect or a facilitatory, preference conditioning effect on subsequent consumption of a low concentration of sucrose, depending on the cues that are present during consumption. The role of context and flavor cues in determining these effects were studied using analysis of the microstructure of licking in mice. Exposure to a high concentration followed by exposure to a low concentration resulted in a transient reduction in mean lick cluster size, which was context dependent (Experiment 1). However, there was no change in the total number of licks or overall consumption. When a flavor that had previously been paired with a high concentration was paired with a low concentration, there was an increase in the total number of licks, and overall consumption, but no change in the mean lick cluster size (Experiment 2). Pairing a high concentration with a flavor in a particular context before pairing the context and flavor compound with a low concentration resulted in abolishing the expression of the flavor preference conditioning effect on the total number of licks and consumption (Experiment 3). These results demonstrate that although context and flavor cues have dissociable effects on licking behavior, their interaction has an antagonistic effect on the behavioral expression of memory.

Use of the Operant Orofacial Pain Assessment Device (OPAD) to Measure Changes in Nociceptive Behavior

We present an operant system for the detection of pain in awake, conscious rodents. The Orofacial Pain Assessment Device (OPAD) assesses pain behaviors in a more clinically relevant way by not relying on reflex-based measures of nociception. Food fasted, hairless (or shaved) rodents are placed into a Plexiglas chamber which has two Peltier-based thermodes that can be programmed to any temperature between 7 °C and 60 °C. The rodent is trained to make contact with these in order to access a reward bottle. During a session, a number of behavioral pain outcomes are automatically recorded and saved. These measures include the number of reward bottle activations (licks) and facial contact stimuli (face contacts), but custom measures like the lick/face ratio (total number of licks per session/total number of contacts) can also be created. The stimulus temperature can be set to a single temperature or multiple temperatures within a session. The OPAD is a high-throughput, easy to use operant assay which will lead to better translation of pain research in the future as it includes cortical input instead of relying on spinal reflex-based nociceptive assays.

Use of the Operant Orofacial Pain Assessment Device (OPAD) to Measure Changes in Nociceptive Behavior

We present an operant system for the detection of pain in awake, conscious rodents. The Orofacial Pain Assessment Device (OPAD) assesses pain behaviors in a more clinically relevant way by not relying on reflex-based measures of nociception. Food fasted, hairless (or shaved) rodents are placed into a Plexiglas chamber which has two Peltier-based thermodes that can be programmed to any temperature between 7 °C and 60 °C. The rodent is trained to make contact with these in order to access a reward bottle. During a session, a number of behavioral pain outcomes are automatically recorded and saved. These measures include the number of reward bottle activations (licks) and facial contact stimuli (face contacts), but custom measures like the lick/face ratio (total number of licks per session/total number of contacts) can also be created. The stimulus temperature can be set to a single temperature or multiple temperatures within a session. The OPAD is a high-throughput, easy to use operant assay which will lead to better translation of pain research in the future as it includes cortical input instead of relying on spinal reflex-based nociceptive assays.

C57BL/6J and DBA/2J mice vary in lick rate and ingestive microstructure

Fluid licking in mice is an example of a rhythmic behavior thought to be under the control of a central pattern generator. Inbred strains of mice have been shown to differ in mean or modal interlick interval (ILI) duration, suggesting a genetic-based variation. We investigated water licking in the commonly used inbred strains C57BL/6J (B6) and DBA/2J (D2), using a commercially available contact lickometer. Results from 20-min test sessions indicated that D2 mice lick at a faster rate than B6 mice (10.6 licks/s vs. 8.5 licks/s), based on analysis of the distribution of short-duration ILIs (50-160 ms). This strain difference was independent of sex, extent of water deprivation or total number of licks. D2 mice also displayed a faster lick rate when the strains were tested with a series of brief (5 s) trials. However, when ingestion over the entire 20-min session was analyzed, it was evident that D2 mice had an overall slower rate of ingestion than B6 mice. This was because of the tendency for D2 mice to have more very long pauses (>30 s) between sequences of licking bursts. Overall, it appeared that D2 mice licked more efficiently, ingesting more rapidly during excursions to the spout that were fewer and farther between.

Effects of benzodiazepine receptor ligands on the ingestion of sucrose, intralipid, and maltodextrin: an investigation using a microstructural analysis of licking behavior in a brief contact test.

Microstructural analysis of licking behavior in the rat was conducted (a) to describe in detail the characteristics of benzodiazepine-induced changes in ingestion and (b) to determine if the changes are consistent with an alteration in palatability. The effects of the benzodiazepine receptor (BZR) agonist midazolam (0.3-3 mg/kg), and the partial inverse agonist Ro 15-4513 (0.3-3 mg/kg), on licking for several concentrations of sucrose, Intralipid, and maltodextrin in a brief contact test were investigated. Midazolam increased the total number of licks for all 3 fluids; conversely, Ro 15-4513 decreased the total number of licks. Midazolam increased mean bout duration for sucrose and maltodextrin drinking and there was a trend toward a similar effect with Intralipid drinking. Ro 15-4513 reduced mean bout duration for all 3 test fluids. These data are discussed in terms of bidirectional changes in fluid palatability by drug actions at BZRs.

Midazolam-induced rapid changes in licking behaviour: evidence for involvement of endogenous opioid peptides.

The role of endogenous opioid peptides in the effects of midazolam on ingestive behaviour was investigated using a detailed analysis of licking behaviour in the rat. Midazolam (1.8 mg/kg i.p.) was administered in combination with either flumazenil (10 and 20 mg/kg i.p.) or naloxone (0.1 and 0.3 mg/kg i.p.). The effect on licking patterns during 60-s exposures to a range of concentrations of a fat emulsion (Intralipid) was then recorded. Midazolam significantly increased the total number of licks for Intralipid by increasing the mean bout duration. This effect is consistent with the proposal that benzodiazepines enhance palatability. Flumazenil and naloxone were ineffective when administered alone, but both drugs blocked the effect of midazolam on total number of licks by selectively attenuating mean bout duration. Midazolam also produced a significant decrease in the intrabout lick rate, probably due to the muscle relaxant effects of this drug. This decrease in the intrabout lick rate was reversed by pretreatment with flumazenil but not by naloxone. The results suggest that endogenous opioids may be important for the palatability effects of midazolam, but may not be involved in the muscle relaxant effects of this drug.

Potentiation of licking in rats by stimulation of both D-1 and D-2 dopamine receptors

Apomorphine-induced licking in rats was assessed by recording the total number of licks by direct observation. Apomorphine induced licking dose dependently. The maximum response was obtained by 0.5 mg/kg of the drug and 30 min after drug administration. Pre-treatment with dopamine antagonists, sulpiride and SCH 23390 decreased the apomorphine effect. Pre-treatment of animals with reserpine+α-methyl-p-tyrosine (AMPT) increased apomorphine-induced licking. In normal rats the D-2 agonist quinpirole and the D-1 agonist SKF 38393 also induced significant licking. The effect of quinpirole or SKF 38393 was decreased by reserpine+AMPT pre-treatment. Combined treatment with SKF 38393 and quinpirole induced more intense licking in both reserpinized and non-reserpinized animals. It is therefore concluded that the apomorphine-induced licking is mediated through both D-1 and D-2 receptors, and that pre-treatment with reserpine hypersensitizes these receptors to the drug effect. However, for either SKF 38393- or quinpirole-induced licking, the presence of endogenous dopamine seems essential.

Intracranial stimulation and one-drop licking in the rat

The present study examined the effects of intracranial stimulation (ICS) of the lateral hypothalamic area (LH) on the lick response of the rat. Rewarding stimulation and/or a drop of water was presented contingent on a lick. Three rats were run on a three-ply multiple schedule. On separate components, licks were reinforced with water, water plus ICS, or ICS alone. For each component, the total number of licks was recorded as well as measures of the burst of licking that occurred after water reinforcement. Initially, nine ICS intensities were used from threshold (T) to threshold plus 400 μA (T + 400 μA). All animals were tested while water deprived, receiving their daily 12-cc ration after the testing session. Then the animals were retested at two ICS intensities (T and T + 200 μA), receiving their daily 12-cc ration of water either ½ h before being tested or at the end of the session. ICS intensities above threshold decreased the rate of responding when the stimulation was combined with water, both in terms of emitted and elicited licking. The operant lick rate for ICS alone was always lower than the lick rate for water alone or for water plus ICS. Water deprivation increased licking during the water component, marginally increased licking in the water-plus-stimulation component, and did not increase licking in the stimulation-only component.

Schedule-induced polydipsia as a function of the interval between food pellets

Previous attempts to investigate the function-relating degree of polydipsia to interval duration have held constant either session length or the number of intervals per session. In the present study both were held constant by exposing rats to progressive-time and retrogressive-time schedules. In the former, the intervals between pellet deliveries became progressively longer during the session; in the latter, they became progressively shorter. Under both schedules, a bitonic relationship was observed between the total number of licks and the interval between food pellets.

Schedule dependence of schedule induced polydipsia and lever pressing

Two male hooded rats maintained at 80% of initial body weight were tested for schedule induced polydipsia at fixed time (FT) intervals of 1.0, 2.0, 3.0, 4.0 and 5.0 min. A total of 180 45 mg pellets were delivered during the test session. Each animal was tested five times at each FT interval. Total number of licks, lever presses and water consumption increased as the FT interval was increased to a maximum at 4.0 min and then decreased at 5.0 min. Although delivery of the food pellet was not contingent upon pressing the lever, lever pressing occurred and followed the same time related function as licking and water consumption. Results were interpreted in terms of increased motor activity attributed to intermittent food delivery.