Matching Items (59)

127920-Thumbnail Image.png

Effects of a 5-HT1B Receptor Agonist on Locomotion and Reinstatement of Cocaine-Conditioned Place Preference after Abstinence from Repeated Injections in Mice

Description

5-HT[subscript 1B] receptors (5-HT[subscript 1B]Rs) modulate behavioral effects of cocaine. Here we examined the effects of the 5-HT[subscript 1B]R agonist 5-propoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-pyrrolo[3,2-b]pyridine (CP94253) on spontaneous and cocaine-induced locomotion and on cocaine-primed

5-HT[subscript 1B] receptors (5-HT[subscript 1B]Rs) modulate behavioral effects of cocaine. Here we examined the effects of the 5-HT[subscript 1B]R agonist 5-propoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-pyrrolo[3,2-b]pyridine (CP94253) on spontaneous and cocaine-induced locomotion and on cocaine-primed reinstatement of conditioned place preference (CPP) in male mice given daily repeated injections of either saline or cocaine (15 mg/kg, IP) for 20 days. In the locomotor activity experiment, testing occurred both 1 and 20 days after the final injection. In the CPP experiment, mice underwent conditioning procedures while receiving the last of their daily injections, which were given either during or ≥2 h after CPP procedures. The CPP procedural timeline consisted of baseline preference testing (days 12–13 of the chronic regimen), conditioning (days 14–19, 2 daily 30-min sessions separated by 5 h), CPP test (day 21), extinction (days 22–34; no injections), CPP extinction test (day 35), and reinstatement test (day 36). Mice that had not extinguished received additional extinction sessions prior to reinstatement testing on day 42. On test days, mice were pretreated with either saline or CP94253 (10 mg/kg, IP). Testing began 30 min later, immediately after mice were primed with either saline or cocaine (5 mg/kg for locomotion; 15 mg/kg for reinstatement). We found that CP94253 increased spontaneous locomotion in mice receiving repeated injections of either saline or cocaine when tested 1 day after the last injection, but had no effect on spontaneous locomotion after 20 days abstinence from repeated injections. Surprisingly, cocaine-induced locomotion was sensitized regardless of whether the mice had received repeated saline or cocaine. CP94253 attenuated expression of the sensitized locomotion after 20 days abstinence. A control experiment in noninjected, drug-naïve mice showed that CP94253 had no effect on spontaneous or cocaine-induced locomotion. Mice reinstated cocaine-CPP when given a cocaine prime, and CP94253 pretreatment attenuated cocaine reinstatement.The findings suggest that stress from repeated saline injections and/or co-housing with cocaine-injected mice may cross-sensitize with cocaine effects on locomotion and that CP94253 attenuates these effects, as well as reinstatement of cocaine-CPP. This study supports the idea that 5-HT[subscript 1B]R agonists may be useful anti-cocaine medications.

Contributors

Agent

Created

Date Created
  • 2017-10-10

127979-Thumbnail Image.png

Preclinical Evidence That 5-HT1B Receptor Agonists Show Promise as Medications for Psychostimulant Use Disorders

Description

Background
5-HT1B receptor agonists enhance cocaine intake during daily self-administration sessions but decrease cocaine intake when tested after prolonged abstinence. We examined if 5-HT1B receptor agonists produce similar abstinence-dependent effects

Background
5-HT1B receptor agonists enhance cocaine intake during daily self-administration sessions but decrease cocaine intake when tested after prolonged abstinence. We examined if 5-HT1B receptor agonists produce similar abstinence-dependent effects on methamphetamine intake.
Methods
Male rats were trained to self-administer methamphetamine (0.1 mg/kg, i.v.) on low (fixed ratio 5 and variable ratio 5) and high (progressive ratio) effort schedules of reinforcement until intake was stable. Rats were then tested for the effects of the selective 5-HT1B receptor agonist, CP 94,253 (5.6 or 10 mg/kg), or the less selective but clinically available 5-HT1B/1D receptor agonist, zolmitriptan (10 mg/kg), on methamphetamine self-administration both before and after a 21-day forced abstinence period during which the rats remained in their home cages.
Results
The inverted U-shaped, methamphetamine dose-response function for intake on the fixed ratio 5 schedule was shifted downward by CP 94,253 both before and after abstinence. The CP 94,253-induced decrease in methamphetamine intake was replicated in rats tested on a variable ratio 5 schedule, and the 5-HT1B receptor antagonist SB 224,289 (10 mg/kg) reversed this effect. CP 94,253 also attenuated methamphetamine intake on a progressive ratio schedule both pre- and postabstinence. Similarly, zolmitriptan attenuated methamphetamine intake on a variable ratio 5 schedule both pre- and postabstinence, and the latter effect was sustained after each of 2 more treatments given every 2 to 3 days prior to daily sessions.
Conclusions
Unlike the abstinence-dependent effect of 5-HT1B receptor agonists on cocaine intake reported previously, both CP 94,253 and zolmitriptan decreased methamphetamine intake regardless of abstinence. These findings suggest that 5-HT1B receptor agonists may have clinical efficacy for psychostimulant use disorders.

Contributors

Agent

Created

Date Created
  • 2017-04-22

128014-Thumbnail Image.png

In silico identification and in vivo validation of miR-495 as a novel regulator of motivation for cocaine that targets multiple addiction-related networks in the nucleus accumbens

Description

MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression and are implicated in the etiology of several neuropsychiatric disorders, including substance use disorders (SUDs). Using in silico genome-wide sequence analyses,

MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression and are implicated in the etiology of several neuropsychiatric disorders, including substance use disorders (SUDs). Using in silico genome-wide sequence analyses, we identified miR-495 as a miRNA whose predicted targets are significantly enriched in the Knowledgebase for Addiction Related Genes (ARG) database (KARG; http://karg.cbi.pku.edu.cn). This small non-coding RNA is also highly expressed within the nucleus accumbens (NAc), a pivotal brain region underlying reward and motivation. Using luciferase reporter assays, we found that miR-495 directly targeted the 3′UTRs of Bdnf, Camk2a and Arc. Furthermore, we measured miR-495 expression in response to acute cocaine in mice and found that it is downregulated rapidly and selectively in the NAc, along with concomitant increases in ARG expression. Lentiviral-mediated miR-495 overexpression in the NAc shell (NAcsh) not only reversed these cocaine-induced effects but also downregulated multiple ARG mRNAs in specific SUD-related biological pathways, including those that regulate synaptic plasticity. miR-495 expression was also downregulated in the NAcsh of rats following cocaine self-administration. Most importantly, we found that NAcsh miR-495 overexpression suppressed the motivation to self-administer and seek cocaine across progressive ratio, extinction and reinstatement testing, but had no effect on food reinforcement, suggesting that miR-495 selectively affects addiction-related behaviors. Overall, our in silico search for post-transcriptional regulators identified miR-495 as a novel regulator of multiple ARGs that have a role in modulating motivation for cocaine.

Contributors

Agent

Created

Date Created
  • 2017-01-13

132142-Thumbnail Image.png

Do 5-HT7R Antagonists have Anti-Cocaine Effects?

Description

Substance abuse costs the United States over $740 billion annually in healthcare, law enforcement, rehabilitation, and decreased work productivity costs. While there are certain clinical treatments for nicotine, opioid,

Substance abuse costs the United States over $740 billion annually in healthcare, law enforcement, rehabilitation, and decreased work productivity costs. While there are certain clinical treatments for nicotine, opioid, and alcohol addiction, there is yet an equivalent treatment for psychostimulant addiction. The 5-HT7 receptor (5-HT7R) is one of the more recently discovered members of the serotonin receptor family. The involvement of 5-HT7Rs in thermoregulation, memory, and circadian rhythms, suggests that the receptor also plays a role in mood regulation, making it a potential target in the treatment of psychiatric disorders. Given’ the distribution of the 5-HT7Rs in the brain and its known cellular functions, the receptor has also been implicated in addiction processes. Most studies to date have mainly focused on psychiatric conditions like depression, having yet to explore the role of 5-HT7Rs in psycho-stimulant behaviors. In our study, the effects of SB 269970(SB), a selective antagonist for 5-HT7Rs, were tested on 8-OH-DPAT induced hypothermia, cocaine-induced locomotion, and fos expression in the nucleus accumbens. We found that SB effectively reversed 8-OH-DPAT induced hypothermia, indicating the drug is indeed binding to the 5-HT7R. However, while cocaine did increase locomotor activity and fos expression in the nucleus accumbens in rats, SB had no effect on either measure. These results suggest that 5-HT7Rs may work through pathways other than motor and should be explored through additional behavioral tests. Other brain regions should also be studied for fos expression to see if there is a region-specific effect of 5-HT7Rs and fos expression. The efficacy of SB to 5-HT7Rs and results of past studies on the drug suggests its potential as a pharmacological treatment for psychostimulant disorders.

Contributors

Agent

Created

Date Created
  • 2019-05

134677-Thumbnail Image.png

Peace, Love, Unity, Respect, and Responsibility: Attitudes on Psychedelic Harm Reduction in the EDM Community

Description

In this field study, 103 individuals from two different music festivals, one in California and one in Michigan, were surveyed to observe current attitudes surrounding harm reduction strategies associated with

In this field study, 103 individuals from two different music festivals, one in California and one in Michigan, were surveyed to observe current attitudes surrounding harm reduction strategies associated with psychedelic drug usage in the EDM scene. Topics from the survey included but were not limited to the chemical testing of substances, frequency of usage, spacing between usage, and adverse effects associated with usage. It was concluded that harm reduction education should become more integrated within the EDM scene in order to provide research-based evidence for ravers to make better decisions for their health. While authorities have pushed "just say no", the lack of education altogether in the community is life threatening. Education is the key to saving minds, bodies, and lives.

Contributors

Agent

Created

Date Created
  • 2016-12

Using Induced Neurons as a New Model for Sporadic Amyotrophic Lateral Sclerosis

Description

Modeling sporadic amyotrophic lateral sclerosis (sALS) has been a challenge since there is no known single gene mutation that triggers disease pathogenesis. Although human induced pluripotent stem cells (hiPSCs) have

Modeling sporadic amyotrophic lateral sclerosis (sALS) has been a challenge since there is no known single gene mutation that triggers disease pathogenesis. Although human induced pluripotent stem cells (hiPSCs) have created new opportunities in studying sALS, they do not retain important age associated phenotypic markers due to the rejuvenation stage that takes place during the reprogramming of somatic cells into hiPSCs. To overcome this obstacle, we performed an alternative method of direct neuronal conversion from patient fibroblasts that utilizes two transcription factors, Ngn2 and Ascl1. These transcription factors were sufficient to initiate direct neuronal conversion and produce induced neurons (iNeurons). Through the positive staining of neuronal markers Map2, Synapsin-1, and Human Nuclear Marker we found that induced neurons do display neuronal features that are seen in mature neurons.

Contributors

Agent

Created

Date Created
  • 2017-05

134455-Thumbnail Image.png

Effects of miR-495 in Cocaine Addiction: Viral Mediated Overexpression and Inhibition of miR-495 Affects Cocaine-Seeking Behavior

Description

MicroRNAs are small, non-coding transcripts that control gene expression by preventing mRNA from translating into proteins. They have been implicated to play a role in many drug addictions. We previously

MicroRNAs are small, non-coding transcripts that control gene expression by preventing mRNA from translating into proteins. They have been implicated to play a role in many drug addictions. We previously found that miR-495 targets several addiction-related genes (ARGs) and is highly expressed in the nucleus accumbens (NAc). We also found miR-495 is downregulated in the NAc following acute cocaine administration, and cocaine motivation measured by breakpoint on a progressive ratio schedule of cocaine reinforcement is decreased when miR-495 is overexpressed. In this study, we manipulated the endogenous levels of miR-495 by using a viral vector. Using an animal model, rats were first trained for self-administration on a fixed ratio (FR) schedule of reinforcement. After they were infused with a lentivirus to overexpress (LV-miR-495) or decrease (LV-Sponge) miR-495, in the NAc shell. The rats were then tested for extinction and reinstatement of cocaine-seeking behavior, which are measures of motivation for cocaine. We measured the relative levels of miR-495 in the NAc shell using qRT-PCR. Our results show that overexpression of miR-495 decreased cocaine-seeking behavior during extinction and cocaine reinstatement, as we hypothesized. Surprisingly, miR-495 LV-sponge also decreased cocaine-seeking behavior in extinction, not as we hypothesized. However, we found that LV-Sponge failed to significantly decrease levels of miR-495 as intended. In conclusion, understanding why LV-Sponge decreased, rather than increased, miR-495 will need further study, however, the results with LV-miR-495 extend previous findings that miR-495 plays a vital role in the molecular mechanism that influences motivation to seek cocaine.

Contributors

Agent

Created

Date Created
  • 2017-05

134358-Thumbnail Image.png

Effects of environmental enrichment on cocaine-seeking behavior in female rats and RNA expression in the Nucleus Accumbens

Description

Substance abuse disorder is a debilitating condition characterized by recurring drug-seeking behaviors and high rates of relapse. In male rats, this tendency to engage in drug-seeking behavior can be inhibited

Substance abuse disorder is a debilitating condition characterized by recurring drug-seeking behaviors and high rates of relapse. In male rats, this tendency to engage in drug-seeking behavior can be inhibited by environmental enrichment (EE) during abstinence. We have shown previously that cocaine-seeking behavior is associated with an increase in addiction-related genes such as Arc and CamkIIa and a decrease in the microRNA miR-495. We have also shown that miR-495 inhibits expression of Arc and CamkIIa post-transcriptionally. Therefore, we hypothesize that reduced cocaine-seeking behavior in EE female rats is associated with a downregulation of these addiction-related genes as well as an upregulation of miR-495 in the NAc shell. Based on previous studies that highlight differences between male and female motivation for cocaine, we also hypothesize that EE will not affect female motivation for cocaine as robustly as males. After acquiring cocaine through self-administration, females were assigned to either an enriched environment (EE) condition or an isolated condition, where they remained during abstinence. They were then given a one-hour cue-reactivity test, during which cocaine-seeking behavior differed significantly between the EE and isolated groups. We also found that the addiction-related genes Arc and CamkIIa were downregulated in the NAc core of EE females. Future research is needed to examine the role of miR-495 in these changes in behavior and gene expression. Overall, the results suggest that EE is protective against relapse to cocaine-seeking in females and may normalize the dysregulation of genes by cocaine.

Contributors

Agent

Created

Date Created
  • 2017-05

135005-Thumbnail Image.png

Defining the effects of ERK/MAPK hyperactivation on the development of GABAergic

Description

Abstract: The RAS/RAF/MEK/ERK (RAS signaling cascade) pathway is a highly conserved biochemical signaling cascade that exists in every mammalian cell. The pathway is highly versatile in functionality due to hundreds

Abstract: The RAS/RAF/MEK/ERK (RAS signaling cascade) pathway is a highly conserved biochemical signaling cascade that exists in every mammalian cell. The pathway is highly versatile in functionality due to hundreds of substrates that regulate metabolism, apoptosis, and proliferation in both adult and developing tissues. The RAS signaling cascade has been examined in the context of cancers since mutations can lead to the disruption of the cell cycle and unregulated cellular proliferation. In addition, germline mutations in the pathway have been shown to cause a group of syndromes known as RASopathies. RASopathies are marked by facial defects, seizures, developmental delays, and cognitive dysfunction often due to enhanced activation of the RAS signaling cascade. Although there are noted factors that play roles in neurological disease, such as a hyperactivated RAS signaling cascade, the pathogenesis of neurological defects is not fully understood. The Newbern lab uses conditional mutagenesis to examine how hyperactivating the RAS/MAPK pathway affects GABAergic neurons in a cortical microcircuit, especially during development. Inhibitory neurons are implicated in seizures and epilepsy is common in RASopathies, thus GABAergic neurons are of particular interest (Rauen, 2013). Gain-of-function ERK was not found to significantly alter global locomotion or anxiety-like behaviors. Interestingly, the mutant mice exhibited freezing behavior in the first twenty-two seconds of the open field assay that appeared to be consistent with absence seizures. Direct EEG recordings confirmed spontaneous seizure activity and mutants had a reduced seizure threshold. We hypothesized that these deficits were due to altered GABAergic neuron number. Indeed, mutant mice exhibited a 30% reduction in total cortical GABAergic neuron number. This effect appeared to be cell subtype specific, where neurons expressing somatostatin (SST) existed in similar numbers among controls and mutants but a significant decrease in the number of those expressing parvalbumin (PV) was observed. I hypothesized that a recently identified GABAergic neuron expressing vasoactive intestinal polypeptide (VIP) would also be affected in such a manner that fewer VIP neurons exist in the mutants than the wildtype. Subsequent histological studies in these mice found there to be no significant difference in VIP populations. Selective affects seem to only have an effect on the development of PV neurons in the cortex. Further studies are underway to define the mechanism responsible for aberrant GABAergic neuron development.

Contributors

Agent

Created

Date Created
  • 2016-05

131284-Thumbnail Image.png

5-HT1B receptor agonist CP 94,253 reduces cocaine intake in female rats post-abstinence and after resuming self-administration

Description

Approximately five million Americans suffer from cocaine use disorder with no FDA approved pharmaceutical to help their path to recovery (Yerby, 2019). Serotonin is heavily implicated in cocaine use and

Approximately five million Americans suffer from cocaine use disorder with no FDA approved pharmaceutical to help their path to recovery (Yerby, 2019). Serotonin is heavily implicated in cocaine use and in the reward system, and is therefore a suggested target for pharmaceuticals aiming to aid in psychostimulant addiction (Sarlin, 2019; Clark and Neumaier, 2001). CP 94,253, a 5-HT1BR agonist, has been shown to increase cocaine intake during maintenance of daily cocaine self-administration, though it has also been shown to decrease intake after a period of forced abstinence (Parsons et al., 1998; Pentowski et al., 2009). While a decrease in cocaine intake post-abstinence is promising post-abstinence, it remains to be seen whether this is a viable option if patients relapse. Most experiments are conducted with male rats, though an increasing amount of data has come to light on the differing effects of drugs on male and female rats (Mennenga and Bimonte-Nelson, 2014). Previous studies conducted through our lab have shown no difference in cocaine self-administration behavior across the estrous cycle phases with CP 94,253. It remains to be seen however, whether CP 94,253 would function dissimilarly in female rats than in male rats. This experiment studied the effects of CP 94,253 on post-abstinence and post-resumption cocaine self-administration in free-cycling female rats across two doses of cocaine. It was shown that CP 94,253 reduces cocaine intake both post-abstinence and post-resumption, suggesting that this pharmacotherapy would work in cases of relapse, and that there are no sex differences in its effects. While more studies should be conducted with locomotion and stress tests, thus far this experiment provides further evidence for the validity of CP 94,253 to be a promising pharmacotherapeutic option for future investigation.

Contributors

Agent

Created

Date Created
  • 2020-05