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Food Reinforcement (food + reinforcement)
Selected AbstractsRepeated withdrawal from ethanol impairs acquisition but not expression of conditioned fearEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2003T. L. Ripley Abstract Repeated withdrawal from ethanol impairs acquisition of conditioned fear [Stephens, D.N., Brown, G., Duka, T. & Ripley, T.L. (2001) Eur. J. Neurosci., 14, 2023,2031]. This study further examined the effect of repeated withdrawal from ethanol on the expression and acquisition of fear conditioning. Following training, presentation of a cue associated with footshock (CS+) resulted in a suppression of operant responding for food reinforcement. In different groups, shock thresholds were manipulated to give weak or severe behavioural suppression. Rats were subsequently chronically treated with ethanol-containing liquid diet either continuously (single withdrawal) or with three withdrawal periods (repeated withdrawal). Ethanol treatment and withdrawal had no effect on conditioned suppression of responding tested 2 weeks after the final withdrawal, at either shock intensity. Nevertheless, extinction of conditioned fear was impaired in the repeated withdrawal group exposed to the higher shock intensity. In the high intensity group, the stimulus,shock association was then reversed, so that the previously neutral conditioned stimulus (CS,) became the CS+. Acquisition of suppression to the new CS+ was significantly less in the animals previously given repeated experience of withdrawal, confirming our previous finding. Thus, repeated withdrawal from ethanol lead to disruption in the acquisition of fear conditioning but had no effect on retrieval of an association formed prior to the ethanol-withdrawal experiences. [source] Stability of hippocampal place cell activity across the rat estrous cycle,HIPPOCAMPUS, Issue 2 2005Jennifer Tropp Abstract Findings from both in vitro and in vivo studies have shown that estrogen exerts pronounced effects on hippocampal morphology and physiology. The degree to which these molecular findings influence hippocampal processing in freely behaving animals is unclear. The present study assessed the effect of the estrous cycle on hippocampal place cells in naturally cycling rats during two behavioral states. Female Sprague-Dawley rats were trained to alternate on a U-shaped runway for food reinforcement. Single-unit recordings of hippocampal CA1 cells were conducted under two conditions: (1) at rest on a holder, and (2) running on the maze. Spatial firing characteristics of the cells were examined at different stages of the estrous cycle (i.e., diestrus, proestrus, and estrus). Specifically, information was collected on (1) mean firing rates; (2) basic place field parameters; and (3) changes in the firing dynamics of these cells (e.g., burst properties). The findings showed a decrease in mean firing rate on the maze during proestrus. However, other basic measures of spatial tuning and burst properties were unchanged. The current study suggests that there is relative stability of hippocampal place cells across the estrous cycle during a well-trained task. © 2004 Wiley-Liss, Inc. [source] Increased Consumption but Not Operant Self-administration of Ethanol in Mice Lacking the RII, Subunit of Protein Kinase AALCOHOLISM, Issue 5 2006Frank M. Ferraro III Background: Accumulating evidence indicates that adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) is involved in the neurobiological responses to ethanol. Previous reports indicate that mice lacking the RII, subunit of PKA (RII,,/,) voluntarily consume more ethanol than wild-type controls (RII,+/+) using 2-bottle testing procedures. Although such procedures primarily measure consummatory behavior, operant self-administration procedures allow analysis of consummatory as well as appetitive or "ethanol-seeking" behavior (i.e., lever pressing is required to gain access to the ethanol solution). Therefore, we determined whether the high ethanol consumption characteristic of RII,,/, mice would be complemented by increased appetitive ethanol-seeking behavior in an operant paradigm. Methods: RII,,/, (n=8) and RII,+/+ (n=8) mice were initially sucrose-faded until they were lever responding for nonsweetened ethanol (10, 14, and 18%). Following the self-administration testing, RII,+/+ and RII,,/, mice were given access to 2 bottles, one containing water and the other ethanol to replicate the voluntary ethanol drinking data previously from our laboratory. Finally, immediately after voluntary consumption all mice were again tested for self-administration of 10% ethanol. Alterations in the reinforcement schedule were also explored as RII,+/+ and RII,,/, mice were tested for self-administration of 10% ethanol at FR-3 and FR-5 schedules. Results: The RII,,/, mice displayed lower operant responding for ethanol and food reinforcement compared with RII,+/+ controls. However, this effect was driven by a significant increase in lever responses made by female RII,+/+ mice. When the excessive lever responses of the female RII,+/+ mice are accounted for, the RII,,/, mice show ethanol lever responses comparable to controls. Following operant self-administration testing, RII,,/, mice of both sexes consumed more ethanol solution compared with RII,+/+ mice during 2-bottle testing. Conclusions: Increased ingestion of ethanol by RII,,/, mice is likely the result of altered PKA activity within neuronal pathways that control ethanol-consummatory behaviors. Conversely, the RII, subunit of PKA appears not to play a critical role in neuronal pathways that regulate appetitive behaviors directed at obtaining ethanol. Finally, increased operant self-administration of food and ethanol by female wild-type mice was absent in female RII,,/, mice, suggesting that normal PKA signaling may be part of a general, and sex-dependent, mechanism involved with reinforcement-seeking behavior. [source] Role of Acetaldehyde in the Discriminative Stimulus Effects of EthanolALCOHOLISM, Issue 6 2002Etienne Quertemont Background: Acetaldehyde has been suggested to mediate some of the effects of ethanol. Acetaldehyde can be produced by the enzyme catalase within the brain after ethanol administration. The catalase inhibitor 3-amino-1,2,4-triazole (AT) reduces the production of acetaldehyde, and AT administration can reduce a number of ethanol-induced behavioral effects; this suggests the involvement of acetaldehyde in these behaviors. However, a role for acetaldehyde in mediating the discriminative stimulus effects of ethanol remains unclear. Methods: The contribution of acetaldehyde to the discriminative stimulus effects of ethanol was investigated by use of a two-lever drug discrimination paradigm with food reinforcement. Male Long-Evans rats were trained to discriminate water from either 1.0 or 2.0 g/kg ethanol. Stimulus substitution tests were conducted with ethanol (0,2.5 g/kg by gavage) and acetaldehyde (0,300 mg/kg intraperitoneally). A cumulative dose-response procedure was then used to investigate the effects of pretreatments with AT (0.5 and 1.0 g/kg intraperitoneally) on ethanol discrimination. Results: Acetaldehyde up to doses that decreased response rates (300 mg/kg) did not substitute for the discriminative stimulus effects of 1.0 or 2.0 g/kg ethanol. In addition, AT pretreatment did not affect the dose-response curves for ethanol discrimination. Conclusions: These results show that exogenous acetaldehyde administration does not produce discriminative stimulus effects that are similar to those of ethanol. Also, pretreatment with the catalase inhibitor did not affect the dose-response curve for ethanol discrimination, and this suggests that endogenously produced acetaldehyde does not contribute to the discriminative stimulus effects of ethanol. Together these results suggest that acetaldehyde does not mediate the discriminative stimulus effects of 1.0 to 2.0 g/kg ethanol. [source] Safety of Administration of Human Butyrylcholinesterase and its Conjugates with Soman or VX in RatsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2010Raymond F. Genovese Rats were trained on a multiple Fixed-Ratio 32, Extinction 30 sec. (FR32, Ext30) schedule of food reinforcement and then injected (i.m.) with Hu BChE (30 mg/kg), equivalent amounts of Hu BChE,soman conjugate (GDC), Hu BChE,VX conjugate, oxotremorine (OXO) (0.316 mg/kg) or vehicle (n = 8, each group). On the day of injection and on 10 subsequent daily sessions, performance was evaluated on the FR32, Ext30 schedule. Neither conjugates nor Hu BChE produced a performance deficit under the schedule. OXO produced a substantial decrease in responding on the day of administration, with complete recovery observed on subsequent sessions. None of the treatments affected circulating acetylcholinesterase (AChE) activity when evaluated 24,72 hr after injection. The dose of Hu BChE produced a 20,000-fold increase above baseline in circulating BChE activity. Pathological evaluation of organ systems approximately 2 weeks following administration of conjugates or Hu BChE alone did not show toxicity. Taken together, these results suggest that Hu BChE , nerve agent conjugates produced following bioscavenger protection against nerve agents soman and VX do not appear to be particularly toxic. These results add to the safety assessment of Hu BChE as a bioscavenger countermeasure against nerve agent exposure. [source] | |||||||||||||