scholarly journals Contribution of Harman and Norharman to the Reinforcing Efficacy of Aqueous Tobacco Smoke Extract Self-Administered by Rats

2021 ◽  
Author(s):  
◽  
Alex John Crowther
Keyword(s):  
Tobacco Smoke ◽  
Fixed Ratio ◽  
Progressive Ratio ◽  
Sprague Dawley ◽  
Self Administration ◽  
Reinforcing Efficacy ◽  
Treatment Groups ◽  
Sprague Dawley Rats ◽  
Reinforcing Agent

<p>Background: Animal models of drug abuse treat nicotine as the primary reinforcing agent that promotes tobacco addiction. However, rodents demonstrate poor self-administration of nicotine despite evidence of tobacco's high abuse potential in humans. This discrepancy has been attributed to other constituents of tobacco smoke that facilitate the development of nicotine dependence. Objectives: This study aimed to determine whether rats would self-administer intravenous an aqueous tobacco smoke extract (TPM) to find evidence if it was more reinforcing than nicotine alone. The study also evaluated the role of tobacco smoke constituent’s harman and norharman in any differences observed. Methods: Firstly, male Sprague-Dawley rats (n=29) were assigned to treatment groups: nicotine (30.0μg/kg/infusion), TPM (containing 30.0μg/kg/infusion nicotine) or saline vehicle. Ability for each treatment to support intravenous self-administration was assessed using spontaneous acquisition of responding on gradually increasing fixed ratio schedules (FR1, FR2, FR5). Subsequent progressive ratio (PR) testing was employed to determine reinforcing efficacy of each treatment. Then a second group of rats (N = 56) were assigned to treatment groups: nicotine alone (30.0 or 75.0μg/kg/infusion) or nicotine combined with norharman (0, 0.4, 2.5 or 6.25μg/kg/infusion) and harman (0.0, 1.6 or 10.0μg/kg, IP), and tested using a similar protocol. Results: Animals readily acquired self-administration responding for TPM and produced higher PR breakpoints (BP) than rats treated with nicotine alone or vehicle. Rats trained to respond for a larger dose of nicotine demonstrated significantly greater response rates than those receiving the lower dose of nicotine. Finally, the addition of harman and norharman to nicotine significantly reduced BP at the lower unit dose of nicotine tested. Conclusions: These findings support the hypothesis that TPM is more reinforcing than nicotine alone. However, the increased reinforcing efficacy of TPM cannot be attributed to the actions of harman and norharman. The potential role of serotonin inhibition in tobacco reward processes is discussed.</p>

scholarly journals Contribution of Harman and Norharman to the Reinforcing Efficacy of Aqueous Tobacco Smoke Extract Self-Administered by Rats

2021 ◽  
Author(s):  
◽  
Alex John Crowther
Keyword(s):  
Tobacco Smoke ◽  
Fixed Ratio ◽  
Progressive Ratio ◽  
Sprague Dawley ◽  
Self Administration ◽  
Reinforcing Efficacy ◽  
Treatment Groups ◽  
Sprague Dawley Rats ◽  
Reinforcing Agent

<p>Background: Animal models of drug abuse treat nicotine as the primary reinforcing agent that promotes tobacco addiction. However, rodents demonstrate poor self-administration of nicotine despite evidence of tobacco's high abuse potential in humans. This discrepancy has been attributed to other constituents of tobacco smoke that facilitate the development of nicotine dependence. Objectives: This study aimed to determine whether rats would self-administer intravenous an aqueous tobacco smoke extract (TPM) to find evidence if it was more reinforcing than nicotine alone. The study also evaluated the role of tobacco smoke constituent’s harman and norharman in any differences observed. Methods: Firstly, male Sprague-Dawley rats (n=29) were assigned to treatment groups: nicotine (30.0μg/kg/infusion), TPM (containing 30.0μg/kg/infusion nicotine) or saline vehicle. Ability for each treatment to support intravenous self-administration was assessed using spontaneous acquisition of responding on gradually increasing fixed ratio schedules (FR1, FR2, FR5). Subsequent progressive ratio (PR) testing was employed to determine reinforcing efficacy of each treatment. Then a second group of rats (N = 56) were assigned to treatment groups: nicotine alone (30.0 or 75.0μg/kg/infusion) or nicotine combined with norharman (0, 0.4, 2.5 or 6.25μg/kg/infusion) and harman (0.0, 1.6 or 10.0μg/kg, IP), and tested using a similar protocol. Results: Animals readily acquired self-administration responding for TPM and produced higher PR breakpoints (BP) than rats treated with nicotine alone or vehicle. Rats trained to respond for a larger dose of nicotine demonstrated significantly greater response rates than those receiving the lower dose of nicotine. Finally, the addition of harman and norharman to nicotine significantly reduced BP at the lower unit dose of nicotine tested. Conclusions: These findings support the hypothesis that TPM is more reinforcing than nicotine alone. However, the increased reinforcing efficacy of TPM cannot be attributed to the actions of harman and norharman. The potential role of serotonin inhibition in tobacco reward processes is discussed.</p>

scholarly journals Vaporized cannabis extracts have reinforcing properties and support conditioned drug-seeking behavior in rats

2019 ◽  
Author(s):  
Timothy G. Freels ◽  
Lydia N. Baxter-Potter ◽  
Janelle M. Lugo ◽  
Nicholas C. Glodosky ◽  
Hayden R. Wright ◽  
...  
Keyword(s):  
Fixed Ratio ◽  
Progressive Ratio ◽  
Sprague Dawley ◽  
Self Administration ◽  
Daily Food ◽  
Sprague Dawley Rats ◽  
Seeking Behavior ◽  
Break Points ◽  
Bona Fide ◽  
Novel Method

ABSTRACTRecent trends in cannabis legalization have increased the necessity to better understand the effects of cannabis use. Animal models involving traditional cannabinoid self-administration approaches have been notoriously difficult to establish and differences in the drug employed and its route of administration have limited the translational value of preclinical studies. To address this challenge in the field, we have developed a novel method of cannabis self-administration using response-contingent delivery of vaporized Δ9-tetrahydrocannabinol-rich (CANTHC) or cannabidiol-rich (CANCBD) complete cannabis extracts. Male Sprague Dawley rats were trained to nosepoke for discrete puffs of CANTHC, CANCBD, or vehicle (VEH) in daily one-hour sessions. Cannabis vapor reinforcement resulted in strong discrimination between active and inactive operanda. CANTHC maintained higher response rates under fixed ratio schedules and higher break points under progressive ratio schedules compared to CANCBD or VEH, and the number of vapor deliveries positively correlated with plasma THC concentrations. Moreover, metabolic phenotyping studies revealed alterations in locomotor activity, energy expenditure, and daily food intake that are consistent with effects in human cannabis users. Furthermore, both cannabis regimens produced ecologically relevant brain concentrations of THC and CBD and CANTHC administration decreased hippocampal CB1 receptor binding. Removal of CANTHC reinforcement (but not CANCBD) resulted in a robust extinction burst and an increase in cue-induced cannabis-seeking behavior relative to VEH. These data indicate that volitional exposure to THC-rich cannabis vapor has bona fide reinforcing properties and collectively support the utility of the vapor self-administration model for the preclinical assessment of volitional cannabis intake and cannabis-seeking behaviors.

scholarly journals The Role of NMDA receptors in rat propofol self-administration

2020 ◽  
Author(s):  
Bei ping Chen ◽  
Xi-xi Huang ◽  
Dong-mei Dong ◽  
Hui Wu ◽  
Tian-qi Zhu ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Neural Plasticity ◽  
Neuronal Development ◽  
Fixed Ratio ◽  
Study Groups ◽  
Sprague Dawley ◽  
Self Administration ◽  
Mk 801 ◽  
Anesthetic Agents

Abstract Background: Propofol is among the most frequently used anesthetic agents, and it has the potential for abuse. The N-methyl-D-aspartate (NMDA) receptors are key mediators neural plasticity, neuronal development, addiction, and neurodegeneration. In the present study, we explored the role of these receptors in the context of rat propofol self-administration. Methods: Sprague-Dawley Rats were trained to self-administer propofol (1.7 mg/kg/infusion) using a fixed-ratio (FR) schedule over the course of 14 sessions (3 h/day). After training, rats were intraperitoneally administered the non-competitive NDMA receptor antagonist MK-801, followed 10 minutes later by a propofol self-administration session. Results: After training, rats successfully underwent acquisition of propofol self-administration, as evidenced by a significant and stable rise in the number of active nose-pokes resulting in propofol administration relative to the number of control inactive nose-pokes (P<0.01). As compared to control rats, rats that had been injected with 0.2 mg/kg MK-801 exhibited a significantly greater number of propofol infusions (F (3, 28) = 4.372, P<0.01), whereas infusions were comparable in the groups administered 0.1 mg/kg and 0.4 mg/kg of this compound. In addition, MK-801 failed to alter the numbers of active (F (3, 28) = 1.353, P>0.05) or inactive (F (3, 28) = 0.047, P>0.05) responses in these study groups. Animals administered 0.4 mg/kg MK-801 exhibited significantly fewer infusions than animals administered 0.2 mg/kg MK-801 (P=0.006, P<0.01). In contrast, however, animals in the 0.4 mg/kg MK-801 group displayed a significant reduction in the number of active nose-poke responses (F(3, 20)=20.8673, P<0.01) and the number of sucrose pellets (F(3, 20)=23.77, P<0.01), while their locomotor activity was increased (F(3, 20)=22.812, P<0.01). Conclusion: These findings indicate that NMDA receptors may play a role in regulating rat self-administration of propofol.

scholarly journals 7,8-Dihydroxyflavone Enhances Cue-Conditioned Alcohol Reinstatement in Rats

2020 ◽  
Vol 10 (5) ◽  
pp. 270 ◽  
Author(s):  
Samuel J. Hogarth ◽  
Elvan Djouma ◽  
Maarten van den Buuse
Keyword(s):  
Body Weight ◽  
Progressive Ratio ◽  
Ethanol Exposure ◽  
Ethanol Solution ◽  
Female Rats ◽  
Male Rats ◽  
Sprague Dawley ◽  
Self Administration ◽  
Bdnf Expression ◽  
Sprague Dawley Rats

Alcohol use disorder (AUD) is a detrimental disease that develops through chronic ethanol exposure. Reduced brain-derived neurotrophic factor (BDNF) expression has been associated with AUD and alcohol addiction, however the effects of activation of BDNF signalling in the brain on voluntary alcohol intake reinstatement and relapse are unknown. We therefore trained male and female Sprague Dawley rats in operant chambers to self-administer a 10% ethanol solution. Following baseline acquisition and progressive ratio (PR) analysis, rats were split into drug and vehicle groups during alcohol lever extinction. The animals received two weeks of daily IP injection of either the BDNF receptor, TrkB, agonist, 7,8-dihydroxyflavone (7,8-DHF), or vehicle. During acquisition of alcohol self-administration, males had significantly higher absolute numbers of alcohol-paired lever presses and a higher PR breakpoint. However, after adjusting for body weight, the amount of ethanol was not different between the sexes and the PR breakpoint was higher in females than males. Following extinction, alcohol-primed reinstatement in male rats was not altered by pretreatment with 7,8-DHF when adjusted for body weight. In contrast, in female rats, the weight-adjusted potential amount of ethanol, but not absolute numbers of active lever presses, was significantly enhanced by 7,8-DHF treatment during reinstatement. Analysis of spontaneous locomotor activity in automated photocell cages suggested that the effect of 7,8-DHF was not associated with hyperactivity. These results suggest that stimulation of the TrkB receptor may contribute to reward craving and relapse in AUD, particularly in females.

scholarly journals Sucrose self-administration and CNS activation in the rat

2011 ◽  
Vol 300 (4) ◽  
pp. R876-R884 ◽  
Author(s):  
Dianne P. Figlewicz ◽  
Jennifer L. Bennett-Jay ◽  
Sepideh Kittleson ◽  
Alfred J. Sipols ◽  
Aryana Zavosh
Keyword(s):  
Energy Homeostasis ◽  
Food Reward ◽  
Fixed Ratio ◽  
Progressive Ratio ◽  
Stria Terminalis ◽  
Self Administration ◽  
Bed Nucleus ◽  
Medial Hypothalamus ◽  
Fos Expression

We have previously reported that administration of insulin into the arcuate nucleus of the hypothalamus decreases motivation for sucrose, assessed by a self-administration task, in rats. Because the pattern of central nervous system (CNS) activation in association with sucrose self-administration has not been evaluated, in the present study, we measured expression of c-Fos as an index of neuronal activation. We trained rats to bar-press for sucrose, according to a fixed-ratio (FR) or progressive-ratio (PR) schedule and mapped expression of c-Fos immunoreactivity in the CNS, compared with c-Fos expression in handled controls. We observed a unique expression of c-Fos in the medial hypothalamus (the arcuate, paraventricular, retrochiasmatic, dorsomedial, and ventromedial nuclei) in association with the onset of PR performance, and expression of c-Fos in the lateral hypothalamus and the bed nucleus of stria terminalis in association with the onset of FR performance. c-Fos expression was increased in the nucleus accumbens of both FR and PR rats. Our study emphasizes the importance of both hypothalamic energy homeostasis circuitry and limbic circuitry in the performance of a food reward task. Given the role of the medial hypothalamus in regulation of energy balance, our study suggests that this circuitry may contribute to reward regulation within the larger context of energy homeostasis.

Cannabidiol treatment reduces the motivation to self-administer methamphetamine and methamphetamine-primed relapse in rats

2018 ◽  
Vol 32 (12) ◽  
pp. 1369-1378 ◽  
Author(s):  
Gracie L Hay ◽  
Sarah J Baracz ◽  
Nicholas A Everett ◽  
Jessica Roberts ◽  
Priscila A Costa ◽  
...  
Keyword(s):  
Lever Press ◽  
Jugular Vein ◽  
Fixed Ratio ◽  
Progressive Ratio ◽  
Preliminary Evidence ◽  
Sprague Dawley ◽  
Psychosocial Effects ◽  
Methamphetamine Dependence ◽  
Sprague Dawley Rats ◽  
Seeking Behavior

Background: Methamphetamine is an addictive stimulant that can cause many adverse physical, psychological and psychosocial effects. Preliminary evidence shows cannabidiol, a non-intoxicating constituent of the cannabis plant, may have efficacy in treating opioid and nicotine dependence. However, no study has yet examined whether cannabidiol treatment might impact on methamphetamine addiction. Aims: The current study investigated whether cannabidiol administration reduces the motivation to self-administer methamphetamine and relapse to methamphetamine-seeking behavior following abstinence. Methods: Thirty-two male Sprague Dawley rats with implanted jugular vein catheters were initially trained to self-administer methamphetamine via lever press during two-hour sessions on a fixed ratio 1 schedule of reinforcement. Rats in experiment 1 ( n=16) then advanced to a progressive ratio reinforcement schedule to examine the effects of cannabidiol (0, 20, 40, and 80 mg/kg intraperitoneal) on motivation to self-administer methamphetamine. Rats in experiment 2 ( n=16) were tested for cannabidiol effects on methamphetamine-primed reinstatement following extinction. Results: Cannabidiol (80 mg/kg, but not 40 mg/kg, or 20 mg/kg) reduced the motivation to self-administer methamphetamine and attenuated methamphetamine-primed relapse to methamphetamine-seeking behavior after extinction. Conclusion: This is the first demonstration that cannabidiol can reduce the motivation to seek and consume methamphetamine, and suggests that cannabidiol might be worth trialing as a novel pharmacotherapy for methamphetamine dependence.

scholarly journals SURVIVAL TIME AND HISTOLOGICAL OUTCOME OF MAJOR ORGANS FOLLOWING HONEY ADMINISTRATION TO ACUTE PARAQUAT-INTOXICATED RATS: A PRELIMINARY STUDY

2017 ◽  
Vol 9 (2) ◽  
pp. 319
Author(s):  
Suk Peng Tang ◽  
Hasnan Jaafar ◽  
Siew Hua Gan ◽  
Kuttulebbai N.s. Sirajudeen ◽  
Siti Amrah Sulaiman
Keyword(s):  
Survival Rate ◽  
Protective Effect ◽  
Survival Time ◽  
Potential Role ◽  
Sprague Dawley ◽  
Treatment Groups ◽  
Sprague Dawley Rats ◽  
Preliminary Study ◽  
Tualang Honey

<p><strong>Objective: </strong>The objective of this research was to investigate the possible protective effect of Tualang honey (TH) in acute paraquat (PQ) toxicity in rats.</p><p><strong>Methods: </strong>A total of 48 male Sprague-Dawley rats aged eight weeks old were used. Oral PQ and TH were administered at 225 mg/kg and 0.2 g/kg, respectively. The effects of single and multiple TH treatmentson PQ-intoxicated rats were then investigated. Single TH treatment groups received TH at 0.5 (PQ+TH0.5h), 2 (PQ+TH2h) or 6 (PQ+TH6h) hours following PQ administration. Multiple TH treatment groups received TH at 0.5, 2 and 6 h (PQ+THtrp) or further daily treatment for the following six days (PQ+TH7d) after PQ administration (n=6 per group). The survival time of the rat was recorded until day 28 before sacrifice, which was followed by a histological examination.</p><p><strong>Results: </strong>Treatment with TH did not improve the survival rate of PQ-intoxicated rats. However, the median survival time of rats that received multiple TH treatments was significantly longer compared to that of the PQ+TH6h group. TH treatment was found to improve the histological outcomes of PQ-intoxicated rats, particularly in the lungs.</p><p><strong>Conclusion: </strong>Our findings suggest the potential role of honey in delaying the toxic effects of PQ.</p>

scholarly journals Reduced sensitivity to reinforcement in adolescent compared to adult Sprague-Dawley rats of both sexes

2017 ◽  
Author(s):  
Emily R. Hankosky ◽  
Sara Ruth Westbrook ◽  
Rachel M. Haake ◽  
Michela Marinelli ◽  
Joshua Michael Gulley
Keyword(s):  
Progressive Ratio ◽  
Schedules Of Reinforcement ◽  
Sprague Dawley ◽  
Self Administration ◽  
Adult Rats ◽  
Saccharin Intake ◽  
Sprague Dawley Rats ◽  
Brain And Behavior ◽  
Motivated Behaviors ◽  
And Behavior

RATIONALE: Adolescence is a period of considerable development of brain and behavior and is the time during which most drug use is initiated. OBJECTIVE: Age-dependent differences in motivated behaviors may be one of the factors that contribute to heightened vulnerability to developing substance use disorders, so we sought to compare age differences in methamphetamine (METH) and saccharin seeking. METHODS: Beginning during adolescence or adulthood, male and female Sprague-Dawley rats were trained to self-administer 0.1% saccharin (via liquid dipper cup) or intravenous METH at one of three doses (0.02, 0.05, 0.08 mg/kg/inf) under increasing fixed ratios schedules of reinforcement. Subsequently, responding for METH (0.02, 0.05, 0.08 or 0.1 mg/kg/inf) under progressive ratio response requirements was assessed in rats that acquired METH self-administration at the highest dose (0.08 mg/kg/inf). RESULTS: We found that adult-onset rats acquired METH self-administration more readily and exhibited higher motivation compared to adolescent-onset rats, although there were no differences in METH intake during acquisition. Adult rats also acquired saccharin self-administration more readily, but in contrast to METH, there were age and sex differences in saccharin intake driven by high levels of responding in adult females. CONCLUSIONS: These findings challenge the prevailing notion that adolescents are hypersensitive to reward and instead raise questions about the potential role of methodological factors on which rodent studies often differ.

scholarly journals Mild DOCA-salt hypertension: sympathetic system and role of renal nerves

2011 ◽  
Vol 300 (5) ◽  
pp. H1781-H1787 ◽  
Author(s):  
Sachin S. Kandlikar ◽  
Gregory D. Fink
Keyword(s):  
Control Period ◽  
Whole Body ◽  
Renal Nerves ◽  
Experimental Hypertension ◽  
Sympathetic Activation ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Salt Hypertension ◽  
Hypertension Development

Excess sympathetic nervous system activity (SNA) is linked to human essential and experimental hypertension. To test whether sympathetic activation is associated with a model of deoxycorticosterone acetate (DOCA)-salt hypertension featuring two kidneys and a moderate elevation of blood pressure, we measured whole body norepinephrine (NE) spillover as an index of global SNA. Studies were conducted in chronically catheterized male Sprague-Dawley rats drinking water containing 1% NaCl and 0.2% KCl. After a 7-day surgical recovery and a 3-day control period, a DOCA pellet (50 mg/kg) was implanted subcutaneously in one group of rats (DOCA), while the other group underwent sham implantation (Sham). NE spillover was measured on control day 2 and days 7 and 14 after DOCA administration or sham implantation. During the control period, mean arterial pressure (MAP) was similar in Sham and DOCA rats. MAP was significantly increased in the DOCA group compared with the Sham group after DOCA administration ( day 14: Sham = 109 ± 5.3, DOCA = 128 ± 3.6 mmHg). However, plasma NE concentration, clearance, and spillover were not different in the two groups at any time. To determine whether selective sympathetic activation to the kidneys contributes to hypertension development, additional studies were performed in renal denervated (RDX) and sham-denervated (Sham-DX) rats. MAP, measured by radiotelemetry, was similar in both groups during the control and DOCA treatment periods. In conclusion, global SNA is not increased during the development of mild DOCA-salt hypertension, and fully intact renal nerves are not essential for hypertension development in this model.

Chronic intravenous administration of V1 arginine vasopressin agonist results in sustained hypertension

1994 ◽  
Vol 267 (2) ◽  
pp. H751-H756 ◽  
Author(s):  
A. W. Cowley ◽  
E. Szczepanska-Sadowska ◽  
K. Stepniakowski ◽  
D. Mattson
Keyword(s):  
Body Weight ◽  
Arginine Vasopressin ◽  
Plasma Catecholamines ◽  
Plasma Osmolality ◽  
Sprague Dawley ◽  
Prolonged Administration ◽  
Chronic Stimulation ◽  
Sustained Hypertension ◽  
Sprague Dawley Rats

Despite the well-recognized vasoconstrictor and fluid-retaining actions of vasopressin, prolonged administration of arginine vasopressin (AVP) to normal animals or humans fails to produce sustained hypertension. The present study was performed to elucidate the role of the V1 receptor in determining the ability of AVP to produce sustained hypertension. Conscious Sprague-Dawley rats with implanted catheters were infused with the selective V1 agonist, [Phe2,Ile3,Orn8]vasopressin (2 ng.kg-1.min-1), for 14 days in amounts that were acutely nonpressor. Blood pressure (MAP), heart rate (HR), body weight, and water intake (WI) were determined daily. Plasma AVP, plasma catecholamines norepinephrine and epinephrine, plasma osmolality, and electrolyte concentration were determined before and on days 1 and 7 of infusion. MAP increased significantly by 10.4 +/- 4.5 mmHg on day 1 and rose to 22 +/- 5 mmHg above control by day 14 (transient decrease on days 6-9) and then fell to control levels after the infusion was stopped. HR did not change significantly. Plasma AVP immunoreactivity increased from 2.5 +/- 0.3 to 10.9 +/- 2.1 pg/ml, whereas norepinephrine tended to fall only on day 1, with epinephrine only slightly elevated on day 7. No evidence of fluid retention was found, and rats lost sodium only on the first day of V1 agonist infusion. Body weight increased throughout the study but was unrelated to the changes of MAP. We conclude that chronic stimulation of V1 receptors results in sustained hypertension in rats.

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