The selective 5-HT2A receptor agonist 25CN-NBOH does not affect reversal learning in mice
Psychedelic 5-hydroxytryptamine 2A receptor (5-HT2AR) agonists are showing promise in the treatment of psychiatric disorders, such as treatment-resistant depression and anxiety. Human studies suggest that enhanced cognitive flexibility may contribute to their clinical efficacy. Both improvement and impairment of cognitive flexibility has been reported with 5-HT2AR ligands, making the link between 5-HT2AR pharmacology and cognitive flexibility equivocal. We tested the selective 5-HT2AR agonist 25CN-NBOH in healthy male C57BL/6JOlaHsd mice in a touchscreen-based mouse reversal learning test. No effects were observed on acqui...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Short Reports Source Type: research

Reward-enhancing effects of d-amphetamine and its interactions with nicotine were greater in female rats and persisted across schedules of reinforcement
Nicotine enhances the value of environmental stimuli and rewards, and reward enhancement can maintain nicotine consumption. Stimulants such as d-amphetamine are misused more by women and are commonly co-used with nicotine. d-Amphetamine potentiates nicotine’s effects in human and animal research. To date, there are no published studies examining this interaction in a reward-enhancement task. The current study sought to investigate the reward-enhancing effects of nicotine alongside and coadministered with d-amphetamine. Further, we evaluated the persistence of reward enhancement across ratio and temporal schedules of rein...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Effects of chemotherapy on operant responding for palatable food in male and female mice
Patients treated with cancer chemotherapeutics frequently report chemotherapy-induced peripheral neuropathy (CIPN), changes in mood (depression and anxiety) and functional impairments. Rodent models of CIPN elicit limited alterations in functional behaviors, which pose challenges in developing preclinical models of chemotherapy-induced behavioral depression. The study examined the consequences of chemotherapy-induced mechanical hypersensitivity (paclitaxel: 32 or 64 mg/kg, cumulative; oxaliplatin: 30 mg/kg, cumulative) on behavioral depression, as measured with operant responding for palatable food during periods of fo...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Sodium butyrate enhances fear extinction and rescues hippocampal acetylcholinesterase activity in a rat model of posttraumatic stress disorder
It is believed that impaired extinction of fear memories is an underlying cause for the development of posttraumatic stress disorder (PTSD). Histone deacetylases (HDAC) are enzymes that modulate extinction by changing the chromatin structure and altering protein synthesis in the brain. Studies show that stress modifies both HDAC activity and cerebral cholinergic neurotransmission. The present work aims to evaluate the effect of sodium butyrate (NaBu), an HDAC inhibitor, on behavioral markers of extinction and biochemical changes in HDAC and acetylcholinesterase activity in the hippocampus. NaBu was administered for 7 days ...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

TrkB agonist 7,8-dihydroxyflavone reverses an induced prepulse inhibition deficit selectively in maternal immune activation offspring: implications for schizophrenia
Reduced brain-derived neurotrophic factor (BDNF) signalling has been implicated in schizophrenia endophenotypes, including deficits in prepulse inhibition (PPI). Maternal immune activation (MIA) is a widely used neurodevelopmental animal model for schizophrenia but it is unclear if BDNF and its receptor, tropomyosin receptor kinase B (TrkB), are involved in PPI regulation in this model. Pregnant Long Evans rats were treated with the viral mimetic, polyinosinic–polycytidylic acid (poly I:C; 4 mg/kg i.v.), and nine male offspring from these dams were compared in adulthood to 11 male Long Evans controls. Offspring underwent...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Opposite genotype-specific effects of serotoninergic treatments on Pavlovian Conditioned Approach in mice of two inbred strains C57 BL/6J and DBA/2J
Individual variability in the response to pharmacological therapies is a major problem in the treatment of psychiatric disorders. Comparative studies of phenotypes expressed by mice of the C57BL/6J (C57) and DBA/2J (DBA) inbred strains can help identify neurobiological determinants of this variability at preclinical levels. We have recently demonstrated that whereas young adult mice of both strains develop sign-tracking in a Pavlovian Conditioned Approach (PCA), a trait associated with dysfunctional behavior in rat models, in full adult C57 mice acquisition of this phenotype is inhibited by pre-frontal cortical (PFC) serot...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Effects of 5-HT2A receptor agonist 2,5-dimethoxy-4-iodoamphetamine on alcohol consumption in Long–Evans rats
The objectives of this study were to determine alcohol consumption after administration of (R)(-)-2,5-dimethoxy-4-iodoamphetamine (DOI) or naltrexone in Long–Evans rats, and to assess the effectiveness of these treatments based on individual differences in alcohol consumption. Adult male Long–Evans rats (N = 16) were given opportunities to orally self-administer a 20% (v/v) ethanol (EtOH) solution using an intermittent access, two-bottle (vs. tap water) choice procedure in their home cages. EtOH consumption and preference, total fluid consumption and food intake were measured. Last, we assessed the effects of naltrexon...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Anorectic interaction and safety of 5-hydroxytryptophan/carbidopa plus phentermine or diethylpropion in rat
This study was designed to determine the anorectic interaction and safety profile of 5-hydroxytryptophan (5-HTP)/carbidopa + diethylpropion and 5-HTP/carbidopa + phentermine combinations in rats. The anorectic effect of individual drugs or in combination was evaluated by the sweetened milk test. Isobologram and interaction index were employed to determine the anorectic interaction between 5-HTP/carbidopa and diethylpropion or phentermine. Plasma serotonin (5-HT) was measured by ELISA. Safety of repeated doses of both combinations in rats was evaluated using the tail sphygmomanometer, cardiac ultrasound, hematic bio...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Discriminative stimulus effects of 3,4-methylenedioxypyrovalerone (MDPV) and structurally related synthetic cathinones
The 3,4-methylenedioxypyrovalerone (MDPV), and other structurally related synthetic cathinones, are popular alternatives to prototypical illicit psychostimulants, such as cocaine and methamphetamine. These drugs are often referred to as ‘bath salts’ and function either as cocaine-like inhibitors of monoamine uptake, or amphetamine-like substrates for dopamine, norepinephrine and serotonin transporters. These studies used male Sprague–Dawley rats trained to discriminate MDPV from saline to evaluate the substitution profiles of structurally related synthetic cathinones, cocaine, and other direct-acting dopamine and nor...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Initial development of a brief assessment of cocaine demand
Cocaine demand is a behavioral economic measure assessing drug reward value and motivation to use drug. The purpose of the current study was to develop a brief assessment of cocaine demand (BACD). Results from the BACD were compared with self-report measures of cocaine use. Participants consisted of treatment-seeking individuals with cocaine use disorder (N = 22). Results revealed that indices of brief demand were significantly associated with various self-report measures of cocaine use. Overall, these results support the utility of a BACD for assessing cocaine demand. (Source: Behavioural Pharmacology)
Source: Behavioural Pharmacology - May 20, 2021 Category: Drugs & Pharmacology Tags: Short Reports Source Type: research

Blockade of α1 subtype GABAA receptors attenuates the development of tolerance to the antinociceptive effects of midazolam in rats
This study examined the GABAA receptor subtype mediation of the tolerance to midazolam-induced antinociception in rats. Midazolam (3.2 mg/kg) significantly reduced the locomotion in rats which was prevented by the selective α1-preferring GABAA receptor antagonist β-carboline-3-carboxylate-t-butyl ester (βCCt) (3.2 mg/kg). Midazolam increased the paw withdrawal threshold as tested by the von Frey filament assay in the complete Freund’s adjuvant-induced inflammatory pain model in rats, and this effect was not altered by βCCt or another α1-preferring GABAA receptor antagonist 3-propoxy-β-carboline hydrochloride (3PBC)...
Source: Behavioural Pharmacology - May 20, 2021 Category: Drugs & Pharmacology Tags: Short Reports Source Type: research

Subanesthetic ketamine with an AMPAkine attenuates motor impulsivity in rats
The concept of ‘impulse control’ has its roots in early psychiatry and today has progressed into a well-described, although poorly understood, multidimensional endophenotype underlying many neuropsychiatric disorders (e.g., attention deficit hyperactivity disorder, schizophrenia, substance use disorders). There is mounting evidence suggesting that the cognitive and/or behavioral dimensions underlying impulsivity are driven by dysfunctional glutamate (Glu) neurotransmission via targeted ionotropic Glu receptor (GluR) [e.g., N-methyl-D-aspartate receptor (NMDAR), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid rece...
Source: Behavioural Pharmacology - May 20, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Combined nicotine and ethanol age-dependently alter neural and behavioral responses in male rats
Use of alcohol (EtOH) and nicotine (Nic) typically begins during adolescence. Smoking and drinking often occur together and lead to a higher consumption of alcohol. Although we have shown that Nic+EtOH is reinforcing in self-administration tests in adolescent male rats, whether Nic+EtOH affects other behaviors or neuronal activity in an age-dependent manner is unknown. To address this, adolescent and adult male rats were given intravenous injections of Nic (30 µg/kg)+EtOH (4 mg/kg) and evaluated for locomotor and anxiety-like behaviors. Regional neuronal activity, assessed by cFos mRNA expression, was measured and used to...
Source: Behavioural Pharmacology - May 20, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Alterations of amygdala-prefrontal cortical coupling and attention deficit/hyperactivity disorder-like behaviors induced by neonatal habenula lesion: normalization by Ecklonia stolonifera extract and its active compound fucosterol
In this study, we investigated behavioral and electrophysiological alterations induced by neonatal habenula lesion (NHL) in rats. In NHL rats, age-dependent behavioral alterations relevant to the ADHD symptoms, such as hyperlocomotion, impulsivity, and attention deficit, were observed. Local field potentials (LFPs) in mesocorticolimbic regions of anesthetized rats were examined with in vivo electrophysiological recordings. Abnormally enhanced synchronization of slow (delta) and fast (gamma) LFP oscillations between the amygdala (AMY) and prefrontal cortex (PFC) was found in juvenile, but not in adult, NHL rats. We further ...
Source: Behavioural Pharmacology - May 20, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research

Valproate selectively suppresses adolescent anabolic/androgenic steroid-induced aggressive behavior: implications for a role of hypothalamic γ-aminobutyric acid neural signaling
This study examined whether valproate would selectively suppress adolescent AAS-induced aggressive behavior and whether GABA neural signaling through GABAA subtype receptors in the latero-anterior hypothalamus (LAH; an area of convergence for developmental and neuroplastic changes that underlie aggression in hamsters) modulate the aggression-suppressing effect of this anticonvulsant medication. Valproate (1.0–10.0 mg/kg, intraperitoneal) selectively suppressed the aggressive phenotype in a dose-dependent fashion, with the effective anti-aggressive effects beginning at 5 mg/kg, intraperitoneally. Microinfusion of the ...
Source: Behavioural Pharmacology - May 20, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research