Maladaptive Sexual Behavior Following Concurrent Methamphetamine and Sexual Experience in Male Rats is Associated with Altered Neural Activity in Frontal Cortex

An overview of the methamphetamine effect on male sexual behavior and reproductive system

Drug addiction and its effect on the behavior and development of children has become a serious problem in our society. Methamphetamine (MA) is one of the most abused psychostimulants in the Czech Republic, and its abuse is rising worldwide. Previous studies have demonstrated the adverse long-term effects of maternal drug abuse on rat offspring. However, the father's contribution as a parent and donor of half of the genetic information is unclear. Previous studies of other psychostimulant drugs indicate that long-term application of MA to adult male rats may induce changes in their reproductive system and lead to changes in rat pup functional and behavioral development. Therefore, the present review aimed to investigate the effect of MA administration on reproductive toxicity and sexual behavior of adult male rats, as well as the impact of paternal MA exposure on behavioral development and locomotor activity in rat offspring.

The Atypical Dopamine Transporter Inhibitor CE-158 Enhances Dopamine Neurotransmission in the Prefrontal Cortex of Male Rats: A Behavioral, Electrophysiological, and Microdialysis Study

BACKGROUND

Dopamine plays a key role in several physiological functions such as motor control, learning and memory, and motivation and reward. The atypical dopamine transporter inhibitor S,S stereoisomer of 5-(((S)-((S)-(3-bromophenyl)(phenyl)methyl)sulfinyl)methyl)thiazole (CE-158) has been recently reported to promote behavioral flexibility and restore learning and memory in aged rats.

METHODS

Adult male rats were i.p. administered for 1 or 10 days with CE-158 at the dose of 1 or 10 mg/kg and tested for extracellular dopamine in the medial prefrontal cortex by means of intracerebral microdialysis and single unit cell recording in the same brain area. Moreover, the effects of acute and chronic CE-158 on exploratory behavior, locomotor activity, prepulse inhibition, working memory, and behavioral flexibility were also investigated.

RESULTS

CE-158 dose-dependently potentiated dopamine neurotransmission in the medial prefrontal cortex as assessed by intracerebral microdialysis. Moreover, repeated exposure to CE-158 at 1 mg/kg was sufficient to increase the number of active pyramidal neurons and their firing frequency in the same brain area. In addition, CE-158 at the dose of 10 mg/kg stimulates exploratory behavior to the same extent after acute or chronic treatment. Noteworthy, the chronic treatment at both doses did not induce any behavioral alterations suggestive of abuse potential (e.g., motor behavioral sensitization) or pro-psychotic-like effects such as disruption of sensorimotor gating or impairments in working memory and behavioral flexibility as measured by prepulse inhibition and Y maze.

CONCLUSIONS

Altogether, these findings confirm CE-158 as a promising pro-cognitive agent and contribute to assessing its preclinical safety profile in a chronic administration regimen for further translational testing.

The association between methamphetamine use and number of sexual partners in men who have sex with men: a systematic review and meta-analysis

Background

Methamphetamine use in men who have sex with men population is significantly higher than that in the general population. Meth use can cause high-risk sexual behaviors, such as having sex with a variety of sexual partners. The aim of this study was to determine the association between meth use and the number of sexual partners in MSM.

Methods

Searching international databases (PubMed (Medline), Scopus, Web of Sciences, Embase (Elsevier), PsycInfo (Ovid), Cochrane CENTRAL (Ovid)) until March 2021 was performed in this meta-analysis using appropriate keywords terms to identify related articles. After retrieving articles in these databases, screening was performed based on the title, abstract and full text of the articles, and the final related studies were selected and evaluated using the Newcastle Ottawa scale checklist.

Results

The sample size consisted 18,455 people in this study, including four cohort studies with a sample size of 15,026 MSM and four case–control studies with a sample size of 3429 MSM. The results of meta-analysis showed that meth use increased the number of sexual partners in MSM (RR: 3.70; % 95 CI: 2.04—6.70). The results of subgroup analyze based on the number of sexual partners showed that in MSM taking meth, the risks of having one to three, four to five, and six or more than six sexual partners were respectively 2.82, 2.98 and 5.89 times higher than those in MSM who did not take meth.

Conclusion

The results showed that meth uses in MSM increased the number of their sexual partners. Due to the fact that increasing the number of sexual partners and high-risk sexual behaviors increase the risk of contracting sexually transmitted diseases such as HIV, it is necessary to adopt control programs to prevent meth use by this group, or to implement programs of reduction in the risk of STIs for this group.

Enhancement of Drug Seeking Following Drug Taking in a Sexual Context Requires Anterior Cingulate Cortex Activity in Male Rats

Individual variance in vulnerability to develop addictions is influenced by social factors. Specifically, drug-taking in a sexual context appears to enhance further drug-seeking behavior in human users, as these users identify the effects of drugs to enhance sexual pleasure as a primary reason for continued drug use. Methamphetamine (Meth) is commonly used in this context. Similarly, male rats that self-administered Meth immediately followed by sexual behavior display enhanced drug-seeking behavior, including attenuation of extinction and increased reinstatement to seeking of Meth-associated cues. Hence, drug-taking in a sexual context enhances vulnerability for addiction. However, the neural mechanisms by which this occurs are unknown. Here the hypothesis was tested that medial prefrontal cortex is essential for this effect of Meth and sex when experienced concurrently. First it was shown that CaMKII neurons in the anterior cingulate area (ACA) were co-activated by both Meth and sex. Next, chemogenetic inactivation of ACA CaMKII cells using AAV5-CaMKIIa-hM4Di-mCherry was shown not to affect Meth-induced locomotor activity or sexual behavior. Subsequently, chemogenetic inactivation of ACA CaMKII neurons during Meth self-administration followed by sexual behavior was shown to prevent the effects of Meth and sex on enhanced reinstatement of Meth-seeking but did not affect enhanced drug-seeking during extinction tests. These results indicate that ACA CaMKII cell activation during exposure to Meth in a sexual context plays an essential role in the subsequent enhancement of drug-seeking during reinstatement tests.

Effect of methamphetamine exposure on sexual behavior and locomotor activity of adult male rats

Drug addiction and its consequences on social life and behavior is currently a worldwide problem. Methamphetamine (MA) is one of the most abused psychostimulants in the Czech Republic. MA elevates mood, increases concentration, reduces appetite, and promotes weight loss. However, high doses and long-term abuse can induce psychosis, hallucinations, paranoia, violent behavior, and can lead to cardiovascular problems. Regarding its high prevalence and negative impact on health and social life, MA needs to be fully investigated. Previous studies have demonstrated the impairing effect of MA drug abuse on female behavior. However, MA's influence on male sexual behavior is not entirely clear. The aim of this study was to examine the effect of MA exposure on sexual behavior and spontaneous locomotor activity of adult male rats. MA was administrated subcutaneously at a dose of 5 mg/kg daily for a period of 30 days. The control group was exposed to saline (SA) at the same time and same volume. At the end of the application period, exposed male rats were paired with non-treated female rats, and their behavior was recorded for 2 h. Sexual mating behavior was described in terms of mounting frequency, intromission frequency, ejaculation frequency, sniffing time, intromission latency and the post-ejaculatory interval. Spontaneous locomotor activity in postnatally exposed male rats was studied using the Laboras apparatus. Acute doses of MA (1 mg/kg) or SA were administrated to probe the sensitizing effect of previous chronic MA exposure. Afterward, the animal was placed in an unknown environment and monitored for 1 h. Behavior was automatically evaluated using Laboras software by analyzing the following parameters: duration of locomotion (s), duration of immobility (s), rearing (vertical exploratory behavior), time spent grooming (s), average speed (mm/s), and distance traveled (m). Our results indicate that MA administration has a negligible effect on the sexual behavior of adult male rats. However, more experiments have to be performed to examine the influence of MA exposure on spermatogenesis and the behavior of offspring. Data from the Laboras test showed that MA exposure has a significant effect on locomotor activity in both acute as well as subchronic MA application. In conclusion, our results show that administration of MA in adult male rats does not affect sexual performance and motivation but does increase locomotor and exploratory activity in an unknown environment.

Strengths, weaknesses, opportunities and threats (SWOT) analysis of reinitiation into methamphetamine abusers: qualitative findings from an exploration of methamphetamine abusers in Shanghai, China

BACKGROUND

Despite high relapse rate among methamphetamine (MA) abusers, there still have been little empirical data to date detecting the risk factors related to craving and relapse from the perspective of MA abusers. Therefore, the aim of this study was to use qualitative research methods exploring the strengths, weaknesses, opportunities and threat factors that could facilitate or impede individuals' abstinence in a real-life context from the perspectives of MA abusers.

AIM

To use qualitative research methods exploring the strengths, weaknesses, opportunities and threat factors relating to individuals' abstinence in a real-life context.

METHOD

Semistructured interviews were conducted with 32 MA abusers recruited in Shanghai guided by open-ended questions on narrating the real-life catalysts and inhibitors related to craving, initiation, relapse and abstinence. All data were transcribed verbatim and analysed using a strengths, weaknesses, opportunities and threats (SWOT) analysis.

RESULTS

The results of the SWOT analysis revealed that contextual factors including peer influence, prevalence and availability of MA, familiar venue of MA use, discrimination, sexual behaviours, alcohol, emotional states and their attitudes towards smoking MA were important factors that contribute to reinitiation and relapse. Surveillance systems, antidrug social workers, vocational skills trainings, moving to another city and family responsibility might serve as counter measures targeting those mentioned weaknesses and threats above.

CONCLUSION

This SWOT analysis highlights the complex nature of relapse. Comprehensive interventions strengthening coping skills such as virtual reality techniques are desperately needed to facilitate individuals' sustained abstinence.

Drug-taking in a socio-sexual context enhances vulnerability for addiction in male rats

Vulnerability to develop addiction is influenced by numerous factors, including social behavior. Specifically, in human users, drug taking in a socio-sexual context appears to enhance further drug-seeking behavior. Users report heightened sexual pleasure as a motivation for further drug use and display risk behaviors even when tested in drug-free state. Here, using a preclinical model of limited voluntary drug use in rats, the hypothesis was tested that methamphetamine (Meth)-taking concurrently with socio-sexual experience increases vulnerability to addiction. Male Sprague Dawley rats were socially housed and underwent limited-access Meth self-administration (maximum 1 mg/kg/session). Meth-taking was either concurrent or non-concurrent with sexual behavior: concurrent animals were mated with a receptive female immediately after each session, while non-concurrent animals gained equivalent sexual experience the week prior. Next, drug-seeking behaviors were measured during cue reactivity, extinction, and reinstatement sessions using different extinction and reinstatement protocols in 4 separate studies. Both groups equally acquired Meth self-administration and did not differ in total Meth intake. However, drug-seeking behavior was significantly higher in concurrent animals during cue reactivity tasks, extinction sessions, and cue- or Meth-induced reinstatement tests. In addition, sexual behavior in the absence of Meth triggered reinstatement of drug-seeking in concurrent animals. These results indicate that Meth-taking in a socio-sexual context significantly enhances vulnerability for drug addiction in male rats. This preclinical paradigm of drug self-administration concurrent with socio-sexual behavior provides a useful model for studying the underlying neurobiology of socially driven vulnerability to drug addiction.