The anti-nociceptive activity of naringenin passes through L-arginine/NO/cGMP/KATP channel pathway and opioid receptors
In conclusion, naringenin could be a promising antinociceptive agent acting through opioid receptors and L-arginine/NO/cGMP/KATP channel pathway. (Source: Behavioural Pharmacology)
Source: Behavioural Pharmacology - September 19, 2021 Category: Drugs & Pharmacology Tags: Research Articles Source Type: research
Nicotinic aspects of the discriminative stimulus effects of arecoline
Despite the evidence that the muscarinic agonist arecoline is a drug of abuse throughout Southeast Asia, its stimulus characteristics have not been well studied. The goal of this work was to understand more about the mediation of discriminative stimulus effects of arecoline. Arecoline (1.0 mg/kg s.c.) was trained as a discriminative stimulus in a group of eight rats. The ability of various cholinergic agonists and antagonists to mimic or antagonize the discriminative stimulus effects of arecoline and to modify its rate-suppressing effects was evaluated. A muscarinic antagonist, but neither of two nicotinic antagonists, was...
Source: Behavioural Pharmacology - September 19, 2021 Category: Drugs & Pharmacology Tags: Research Articles Source Type: research
Evaluation of acute and chronic nociception in subchronically administered MK-801-induced rat model of schizophrenia
In conclusion, MK-801 induced antinociception effects for thermal stimuli in rats that were consistent with the decreased pain sensitivity observed in schizophrenia patients. Additionally, the amplified biphasic response exhibited by the MK-801 group in the formalin-induced spontaneous nociception test affirms the suitability of the test as a model of acute to delayed pain transition. (Source: Behavioural Pharmacology)
Source: Behavioural Pharmacology - September 19, 2021 Category: Drugs & Pharmacology Tags: Research Articles Source Type: research
Prenatal exposure to valproic acid and treatment with intranasal oxytocin have sex-specific effects on behavior in Long Evans rats
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social behaviors and communication. In rodents and humans, prenatal exposure to antiepileptic valproic acid is associated with an increased risk for autistic-like characteristics. One potential treatment is oxytocin, a prosocial neuropeptide that can be delivered intranasally. However, the sex-specific effects of valproic acid exposure and intranasal oxytocin treatment on behavior have not been fully explored. Pregnant Long Evans rats were administered valproic acid (500 mg/kg) or saline midday on gestational day 12, and after ...
Source: Behavioural Pharmacology - September 19, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Assessment of antidepressant-like effects of dextromethorphan on differential reinforcement of low-rate 72-s performance in rats
The effectiveness of ketamine for treatment-resistant depression along with several other clinical advantages, such as rapid onset and reduced adverse effects associated with serotonin transporter inhibition, has garnered interest in other similar acting psychedelics as novel antidepressant drugs. The antitussive dextromethorphan exhibits glutamate N-methyl-d-aspartate receptor antagonism, sigma-1 receptor agonism, and serotonin reuptake inhibition, which has exhibited antidepressant effects in limited human studies and animal models. The present study sought to further examine dextromethorphan using a differential reinfor...
Source: Behavioural Pharmacology - September 19, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Norepinephrine as a spatial memory reset signal
Contextual information is represented in the hippocampus (HPC) partially through the recruitment of distinct neuronal ensembles. It is believed that reactivation of these ensembles underlies memory retrieval processes. Recently, we showed that norepinephrine input from phasic locus coeruleus activation induces hippocampal plasticity resulting in the recruitment of new neurons and disengagement from previously established representations. We hypothesize that norepinephrine may provide a neuromodulatory mnemonic switch signaling the HPC to move from a state of retrieval to encoding in the presence of novelty, and therefore, ...
Source: Behavioural Pharmacology - September 19, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Characterization of 3,4-methylenedioxypyrovalerone discrimination in female Sprague–Dawley rats
3,4-Methylenedioxypyrovalerone (MDPV), one of several synthetic cathinones, is a popular constituent of illicit ‘bath salts’. In preclinical studies utilizing drug discrimination methods with male rodents, MDPV has been characterized as similar to both cocaine and 3,4-methylenedioxymethamphetamine-hydrochloride (MDMA). Whereas few drug discrimination studies have utilized female rats, the current study evaluated the discriminative stimulus effects of MDPV in 12 adult female Sprague–Dawley rats trained to discriminate 0.5 mg/kg MDPV from saline under a fixed ratio 20 schedule of food reinforcement. Stimulus substituti...
Source: Behavioural Pharmacology - August 14, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Orexin-2 receptor antagonism in the cornu ammonis 1 region of hippocampus prevented the antinociceptive responses induced by chemical stimulation of the lateral hypothalamus in the animal model of persistent pain
Orexins are excitatory neuropeptides, mainly produced by neurons located in the lateral hypothalamus, which project to many brain areas. The orexinergic system plays a fundamental role in arousal, sleep/wakefulness, feeding, energy homeostasis, motivation, reward, stress and pain modulation. As a prominent part of the limbic system, the hippocampus has been involved in formalin-induced nociception modulation. Moreover, hippocampus regions express both orexin-1 (OX1) and orexin-2 (OX2) receptors. The present study investigated the role of OX2 receptors (OX2R) within the cornu ammonis 1 (CA1) region of the hippocampus in the...
Source: Behavioural Pharmacology - August 14, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Effects of food restriction on the conditioned reinforcing properties of an opioid-associated stimulus
Food restriction promotes drug self-administration; however, the effects of food restriction on the conditioned reinforcing properties of drug-associated stimuli are less clear. We tested the extent to which food restriction modified the conditioned reinforcing properties of a remifentanil-associated stimulus following conditioning with 3.2 or 1.0 μg/kg/infusion of remifentanil. First, we provided restricted (20 g/day standard chow) or ad libitum access to standard chow to rats. Second, within each feeding condition, we exposed rats to 20 intravenous infusions of remifentanil and 20 stimulus presentations that were deli...
Source: Behavioural Pharmacology - August 14, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Nicotine-like discriminative and aversive effects of two α4β2-selective nicotine agonists, ispronicline and metanicotine
An attempt to determine the receptor selective nature of some of nicotine’s behavioral effects was undertaken through the evaluation of the ability of two nicotinic α4β2*-selective receptor agonists to produce nicotine-like effects and modify rates of responding in a discrimination assay and in an aversive stimulus assay. A group of eight rats was trained to discriminate the presence of 1 mg/kg nicotine base. Another group of 4–6 rats was trained to report the aversive effects of nicotine by selecting a lever that produced one food pellet over a second lever that produced two food pellets and an intravenous injecti...
Source: Behavioural Pharmacology - August 14, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Alteration of the PKA-CREB cascade in the mPFC accompanying prepulse inhibition deficits: evidence from adolescent social isolation and chronic SKF38393 injection during early adolescence
Prepulse inhibition (PPI) refers to the inhibition of the startle reflex that occurs when the startling stimulus is preceded by a weak prestimulus. Altered adolescent mPFC circuitry induced by early-life adversity might be a key source of PPI deficits. The current study focused on variations in the cyclic AMP (cAMP)/protein kinase A (PKA)-cAMP-response element-binding protein (CREB) pathway in the medial prefrontal cortex (mPFC). We found a negative relationship between PPI and the PKA-CREB cascade during adolescence by employing both developmental and pharmacologic manipulations. Experiment 1, with the early adolescent so...
Source: Behavioural Pharmacology - August 14, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Escalating morphine dosage fails to elicit conditioned analgesia in a preclinical chronic neuropathic pain model
Many people with chronic pain escalate their opioid dosage to counteract tolerance effects. A treatment regimen consisting of placebos admixed with opioids has been suggested as a possible therapeutic option that could reduce the harm of long-term opioid use. However, the analgesic efficacy of such a regimen requires further investigation before widespread adoption. We have recently reported that a 4-day pharmacological conditioning procedure, which paired morphine (6 mg/kg) with contextual cues, elicited placebo analgesia in subpopulations of male (35%) and female (25%) rats with sciatic nerve chronic constriction injur...
Source: Behavioural Pharmacology - August 14, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Antidepressant-like effects of dezocine in mice: involvement of 5-HT1A and κ opioid receptors
This study examined the potential antidepressant-like activity of dezocine in mice. Male ICR mice were used in the forced swimming test, the tail suspension test, the warm water tail withdrawal test and locomotor activity test to test the effects of dezocine (0.3–3.0 mg/kg). The 5-HT1A receptor antagonist WAY-100635 (1 mg/kg), the μ-opioid receptor antagonist β-funaltrexamine (2 mg/kg) and the κ-opioid receptor agonist U50488 (1 mg/kg) were also studied in combination with dezocine. Dezocine produced a dose-dependent decrease in the immobility time in the forced swimming test and tail suspension test at doses that did...
Source: Behavioural Pharmacology - August 14, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Positive effects of roflumilast on behavior, neuroinflammation, and white matter injury in mice with global cerebral ischemia
Inhibition of phosphodiesterase 4 (PDE4) is a promising pharmacological strategy for the treatment of cerebral ischemic conditions. To increase the relevance and increase the translational value of preclinical studies, it is important to conduct experiments using different animal species and strains, different animal models, and to evaluate long-term functional outcomes after cerebral ischemia. In the present study, the effects of the selective PDE4 inhibitor roflumilast were evaluated in vivo and in vitro. Balb/c mice were subjected to bilateral common carotid artery occlusion (BCCAO) and tested during 21 days in multiple...
Source: Behavioural Pharmacology - August 14, 2021 Category: Drugs & Pharmacology Tags: Research Reports Source Type: research
Some effects of putative G-protein biased mu-opioid receptor agonists in male rhesus monkeys
G-protein-biased mu-opioid receptor (GPB-MOR) agonists are an emerging class of compounds being evaluated as candidate analgesics and agonist medications for opioid use disorder. Most of the basic pharmacology of GPB-MOR agonists has been conducted in rodents and much less is known how the basic behavioral pharmacology of these compounds translates to nonhuman primates. The present study determined the antinociceptive potency and time course of three putative GPB-MOR agonists: (+)-oliceridine (i.e. TRV130), SR14968, and SR17018 in male rhesus monkeys (n = 3). In addition, the respiratory effects of these compounds were...
Source: Behavioural Pharmacology - July 16, 2021 Category: Drugs & Pharmacology Tags: Short Reports Source Type: research
