Tactile Stimulation in Adult Rats Modulates Dopaminergic Molecular Parameters in the Nucleus Accumbens Preventing Amphetamine Relapse.

Amphetamine (AMPH) is a psychostimulant drug frequently related to addiction, which is characterized by functional and molecular changes in the brain reward system, favoring relapse development and pharmacotherapies have shown low effectiveness. Considering the beneficial influences of tactile stimulation (TS) in different diseases that affect the central nervous system (CNS), here we evaluated if TS applied in adult rats could prevent or minimize the AMPH-relapse behavior also accessing molecular neuroadaptations in the Nucleus accumbens (NAc). Following AMPH conditioning in the conditioned place preference (CPP) paradigm, male rats were submitted to TS (15-min session, 3 times a day, for 8 days) during the drug abstinence period, which were re-exposed to the drug in the CPP paradigm for additional 3 days for relapse observation and molecular assessment. Our findings showed that besides AMPH relapse; TS prevented the dopamine transporter (DAT), dopamine 1 receptor (D1R), tyrosine hydroxylase (TH), mu opioid receptor (MOR) increase and AMPH-induced delta FosB (ΔFosB). Based on these outcomes, we propose TS as a useful tool to treat psychostimulant addiction, which subsequent to clinical studies; it could be included in detoxification programs together with pharmacotherapies and psychological treatments already conventionally established.

The Association Between Abstinence Period And Semen Parameters: Results In Normal Samples And Different Sperm Pathology

Purpose: The length of sexual abstinence seems to influence sperm quality. However, few data on the relevance of abstinence time in pathological sperm samples are available. With our study, we look for associations of abstinence length and semen quality. Methods: We studied semen samples from 4423 men undergoing fertility evaluation. Sperm concentration, percentage of progressively motile spermatozoa, total motile sperm count, percentage of spermatozoa with normal morphology, were compared after each day and 0-2, 3-7 and >7 days of abstinence.Results: We found that a longer abstinence time was related to higher sperm concentration in normal semen samples (P<0.001) and in semen samples with any sperm pathology (P<0.001, P=0.004) with the exception of oligozoospermia (P=0.125). Longer abstinence time was also associated with significantly reduced progressive motility in normal samples (P<0.001) and in cases of teratozoospermia (P<0.001). In normal samples a higher percentage of sperm were morphologically normal after a shorter abstinence period (P=0.03); in oligoasthenoteratozoospermia (OAT) samples, this was the case after a longer abstinence period (P=0.013).Conclusion: A longer abstinence time is associated with higher sperm concentration, whereas sperm motility is optimal after shorter abstinence times; results on morphology are controversial. The recommendation on abstinence time needs to be adjusted in relation to the parameter that needs to be improved.

The Role of Serotonin in MDMA Self-administration in Rats

<p>Rationale: The profile of acquisition for MDMA self-administration differs from that of amphetamine and cocaine self-administration in that fewer rats meet an acquisition criterion and the latency to acquisition is longer. These characteristics of MDMA self-administration may be because it preferentially stimulates serotonin (5HT) release whereas self-administration has generally been attributed to enhanced dopamine (DA) neurotransmission. Because 5HTergic agonists are not self-administered and increased synaptic 5HT decreased self-administration of other drugs, MDMA self-administration may be initially inhibited by the pronounced 5HT response. Accordingly, the acquisition of MDMA self-administration might proceed as a result of deficits in 5HT neurotransmission and a corresponding disinhibition of DA neurotransmission. Objective: The primary objective was to determine the role of 5HT in the acquisition and maintenance of MDMA self-administration. Methods: MDMA-induced increases of extracellular 5HT and DA and their primary metabolites were measured in the DA terminal regions of the nucleus accumbens (NAc) using in vivo microdialysis, prior to the commencement of MDMA self-administration. The relationship between MDMA-induced increases of neurotransmitter levels and the acquisition of MDMA self-administration was assessed. A subsequent study depleted brain 5HT by administering the neurotoxin, 5,7 – DHT, or vehicle into the lateral ventricle of the left hemisphere, prior to the commencement of MDMA self-administration. The proportion of subjects that acquired MDMA self-administration and the latency to acquire MDMA self-administration was compared for the two groups. In order to determine effects of MDMA self-administration on 5HT and DA responses, behaviours that reflect 5HT and/or DA neurotransmission were measured 5 or 14 days after self-administration of 165 mg/kg MDMA, or 14 days after vehicle self-administration. These time periods were chosen because they reflect a period of 5HT deficits (5 days) and recovery (14 days). Finally, the effect of abstinence on MDMA self-administration was measured. Results: The MDMA-induced increase of extracellular 5HT was significantly lower for the group that subsequently acquired MDMA self-administration but the MDMA-induced increase in DA was not different from the group that failed to acquire self-administration. 5, 7-DHT administration significantly decreased tissue levels of 5HT, but not DA. MDMA self-administration was facilitated by the lesion; 100% of the lesion group acquired MDMA self-administration, whereas only 50% of the control group acquired self-administration. Five days following the last MDMA self-administration session, DAergic behaviours were enhanced and 5HTergic behaviours were reduced relative to the control group. These differences in 5HTergic mediated behaviours were not apparent 14 days after self-administration but the DAergic behaviours remained elevated. The pattern of self-administration did not differ as a function of the length of the abstinence period. Conclusions: The variability in acquisition of MDMA self-administration was related to the magnitude of the 5HT response evoked by initial exposure to MDMA. These findings suggested that predisposing differences in the 5HT response might explain differences in the variability in acquisition of MDMA self-administration. The negative impact of 5HT on the acquisition of MDMA self-administration was clearly demonstrated following a 5, 7-DHT lesion. Thus, 5HT limits the development of MDMA self-administration. With repeated exposure to self-administered MDMA, behavioural responses indicative of 5HT activation were reduced whereas behavioural indices of DA activation were increased. The maintenance of MDMA self-administration was comparable regardless of whether there was a forced abstinence period or not. These data are consistent with the hypotheses that 5HT is inhibitory to the acquisition, but not the maintenance, of MDMA self-administration. Rather, the maintenance of self-administration might reflect sensitised DA responses that became apparent following repeated exposure.</p>

The Role of Serotonin in MDMA Self-administration in Rats

<p>Rationale: The profile of acquisition for MDMA self-administration differs from that of amphetamine and cocaine self-administration in that fewer rats meet an acquisition criterion and the latency to acquisition is longer. These characteristics of MDMA self-administration may be because it preferentially stimulates serotonin (5HT) release whereas self-administration has generally been attributed to enhanced dopamine (DA) neurotransmission. Because 5HTergic agonists are not self-administered and increased synaptic 5HT decreased self-administration of other drugs, MDMA self-administration may be initially inhibited by the pronounced 5HT response. Accordingly, the acquisition of MDMA self-administration might proceed as a result of deficits in 5HT neurotransmission and a corresponding disinhibition of DA neurotransmission. Objective: The primary objective was to determine the role of 5HT in the acquisition and maintenance of MDMA self-administration. Methods: MDMA-induced increases of extracellular 5HT and DA and their primary metabolites were measured in the DA terminal regions of the nucleus accumbens (NAc) using in vivo microdialysis, prior to the commencement of MDMA self-administration. The relationship between MDMA-induced increases of neurotransmitter levels and the acquisition of MDMA self-administration was assessed. A subsequent study depleted brain 5HT by administering the neurotoxin, 5,7 – DHT, or vehicle into the lateral ventricle of the left hemisphere, prior to the commencement of MDMA self-administration. The proportion of subjects that acquired MDMA self-administration and the latency to acquire MDMA self-administration was compared for the two groups. In order to determine effects of MDMA self-administration on 5HT and DA responses, behaviours that reflect 5HT and/or DA neurotransmission were measured 5 or 14 days after self-administration of 165 mg/kg MDMA, or 14 days after vehicle self-administration. These time periods were chosen because they reflect a period of 5HT deficits (5 days) and recovery (14 days). Finally, the effect of abstinence on MDMA self-administration was measured. Results: The MDMA-induced increase of extracellular 5HT was significantly lower for the group that subsequently acquired MDMA self-administration but the MDMA-induced increase in DA was not different from the group that failed to acquire self-administration. 5, 7-DHT administration significantly decreased tissue levels of 5HT, but not DA. MDMA self-administration was facilitated by the lesion; 100% of the lesion group acquired MDMA self-administration, whereas only 50% of the control group acquired self-administration. Five days following the last MDMA self-administration session, DAergic behaviours were enhanced and 5HTergic behaviours were reduced relative to the control group. These differences in 5HTergic mediated behaviours were not apparent 14 days after self-administration but the DAergic behaviours remained elevated. The pattern of self-administration did not differ as a function of the length of the abstinence period. Conclusions: The variability in acquisition of MDMA self-administration was related to the magnitude of the 5HT response evoked by initial exposure to MDMA. These findings suggested that predisposing differences in the 5HT response might explain differences in the variability in acquisition of MDMA self-administration. The negative impact of 5HT on the acquisition of MDMA self-administration was clearly demonstrated following a 5, 7-DHT lesion. Thus, 5HT limits the development of MDMA self-administration. With repeated exposure to self-administered MDMA, behavioural responses indicative of 5HT activation were reduced whereas behavioural indices of DA activation were increased. The maintenance of MDMA self-administration was comparable regardless of whether there was a forced abstinence period or not. These data are consistent with the hypotheses that 5HT is inhibitory to the acquisition, but not the maintenance, of MDMA self-administration. Rather, the maintenance of self-administration might reflect sensitised DA responses that became apparent following repeated exposure.</p>

Cannabidiol Modulates the Expression of Neurotrophin Signaling Pathway in Chronic Exposure Methamphetamine Rats During Abstinence Period

Several neuropsychiatric disorders such as addiction have indicated variations in the levels of neurotrophic factors. As an extremely addictive stimulant, Methamphetamine (METH) is associated with rising levels of abuse on a global scale. We have recently demonstrated that repeated intracerebroventricular (ICV) of cannabidiol (CBD), the most important non-psychotomimetic compound, can lead to diminished impairing memory and hippocampal damage caused by chronic exposure METH (CEM) in rats over the abstinence period. Furthermore, the results indicated a possible contribution of the neurotrophin signaling pathway (NSP) in regulating neurogenesis and survival. The next study was intended to evaluate whether these remained effects as measured in molecular pathway after abstinence period. In this regard, animals were given 2 mg/kg METH twice daily for a 10-day period. Then, we adopted real-time polymerase chain reaction (PCR) throughout the 10-day abstinence period for assessing the CBD’s effect (10 and 50 μg/5 μl) on the levels of the mRNA expression of the NSP. The findings suggested that CEM, compared with the control group in the hippocampus, downregulated mRNA expression of NSP. Moreover, a dosage of 50 μg/5μl CBD may possibly enhance the mRNA expression level of BDNF/TrkB and NGF/TrkA in the hippocampus. Besides, the expression raf-1 mRNA level could be reversed significantly by both doses of CBD. According to our results, CBD may partly bring about the neuroprotective effects by modulating the NSP. These findings set forth solid evidence demonstrating that CBD is a protection factor attributed to neuropsychiatric disorders such as METH addiction.

P–031 The effect of ejaculatory abstinence period on embryological and clinical outcomes in ICSI cycles: A retrospective analysis of 3,353 cycles

Study question Does ejaculatory abstinence period in male affect embryological and pregnancy outcomes following fresh embryo transfers in ICSI cycles? Summary answer Shorter ejaculatory abstinence period is associated with lower triploid zygotes rate per ICSI cycle but it does not affect clinical outcomes after fresh embryo transfers. What is known already Lower sperm quality may negatively impact on fertilisation rate and embryo morphokinetic parameters after ICSI and the effect of the ejaculatory abstinence period before semen collection on seminal parameters and sperm quality has been widely reported. However, the impact of ejaculatory abstinence on clinical outcomes is still controversial. WHO (World Health Organization) guideline recommended that abstinence period should be 2–7 days. Even so, there are no larger prospective trials determining the optimal timing for ejaculatory abstinence period for infertile couples. Study design, size, duration This is a single center retrospective observational study of 3,353 fresh cycles from January 2017 to December 2020. Semen analysis was done according to the WHO criteria. Exclusion criteria for this study were frozen gametes and cycles with no retrieved oocytes. Primary outcomes were fertilization rate and triploid zygotes rate. Secondary outcomes were blastulation rate, ongoing pregnancy rate and live birth rate per fresh embryo transfer. Participants/materials, setting, methods The correlation between ejaculatory abstinence and continuous outcomes was evaluated by Spearman’s correlation analysis in order to detect potential non-linear associations. Generalized linear model and logistic regression were used, respectively for continuous and binary outcomes, in order to adjust for confounders such as female age, male age, number of retrieved oocytes, percentage of mature oocytes, infertility causes, seminal volume, sperm concentration and total progressive sperm motility. A p value &lt;0.05 was considered significant. Main results and the role of chance The male mean age was 40.3±5.5 and mean duration of abstinence was 2.9±1.7 days. The mean age of female patients was 38.2±4.0. Higher ejaculatory abstinence period was associated with a higher sperm concentration (Spearman p = 3.1x10–6) but not with a higher total sperm progressive motility. Even so, no significant correlation with EA were observed when considering fertilization rate, blastulation rate, ongoing pregnancy and live birth rate per transfer in analyzed cycles. Triploid zygote rate was positively associated with a higher ejaculatory abstinence period. For the ejaculatory abstinence period of 1 day (n = 64), 2 days (n = 1523), 3 days (n = 1032), 4 days (n = 408), 5 days (n = 174), 6 days (n = 47) and ≥7 days (n = 105) the mean triploid rate was 2.4%, 2.4%, 2.5%, 4.1%, 3.6%, 5.4% and 4.3%, respectively (Spearman p = 9x10–3). Triploid zygote rate was independent of semen volume, concentration and total progressive motility. Limitations, reasons for caution This is a large observational study with a retrospective data collection. Despite our methodological approach, the presence of biases related to retrospective design can not be excluded and it may be a reason for caution. Wider implications of the findings: Our results demonstrate that ejaculatory abstinence period do not affect blastulation, ongoing pregnancy and live birth rates. The current findings discourage an abstinence time longer than 3 days due to its association with a higher abnormal fertilization rate. Trial registration number Not applicable

The Association Between Abstinence Period and Semen Parameters: Results in Normal Samples and Different Sperm Pathology

Purpose: The length of sexual abstinence seems to influence sperm quality. However, few data on the relevance of abstinence time in pathological sperm samples are available. With our study, we look for associations of abstinence length and semen quality. Methods: We studied semen samples from 4423 men undergoing fertility evaluation. Sperm concentration, percentage of progressively motile spermatozoa, total motile sperm count, percentage of spermatozoa with normal morphology, were compared after each day and 0-2, 3-7 and >7 days of abstinence. Results: We found that a longer abstinence time was related to higher sperm concentration in normal semen samples (P<0.001) and in semen samples with any sperm pathology (P<0.001, P=0.004) with the exception of oligozoospermia (P=0.125). Longer abstinence time was also associated with significantly reduced progressive motility in normal samples (P<0.001) and in cases of teratozoospermia (P<0.001). In normal samples a higher percentage of sperm were morphologically normal after a shorter abstinence period (P=0.03); in oligoasthenoteratozoospermia (OAT) samples, this was the case after a longer abstinence period (P=0.013). Conclusion: A longer abstinence time is associated with higher sperm concentration, whereas sperm motility is optimal after shorter abstinence times; results on morphology are controversial. The recommendation on abstinence time needs to be adjusted in relation to the parameter that needs to be improved.