Effects of Acute Doses of Prosocial Drugs Methamphetamine and Alcohol on Plasma Oxytocin Levels

Abstract

Many drugs, including alcohol and stimulants, demonstrably increase sociability and verbal interaction and are recreationally consumed in social settings. One drug, 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”), appears to produce its prosocial effects by increasing plasma oxytocin levels, and the oxytocin system has been implicated in responses to several other drugs of abuse. Here, we sought to investigate the effects of two other “social” drugs on plasma oxytocin levels: methamphetamine and alcohol. Based on their shared capacity to enhance sociability, we hypothesized that both methamphetamine and alcohol would increase plasma oxytocin. In Study 1, 11 healthy adult volunteers attended three sessions during which they received methamphetamine (10mg or 20mg) or placebo under double blind conditions. Subjective drug effects, cardiovascular effects, and plasma oxytocin were measured at regular intervals throughout the sessions. In Study 2, 8 healthy adult volunteers attended a single session during which they received one beverage containing placebo, and then a beverage containing alcohol (0.8 g/kg). Subjective effects, breath alcohol levels, and plasma oxytocin were measured at regular intervals. Both methamphetamine and alcohol produced their expected physiological and subjective effects, but neither drug increased plasma oxytocin levels. The neurobiological mechanisms mediating the prosocial effects of drugs such as alcohol and methamphetamine remain to be identified.

Methamphetamine abstinence induces changes in μ-opioid receptor, oxytocin and CRF systems: Association with an anxiogenic phenotype

“…While the effects of acute METH administration on the central OTR system and plasma oxytocin levels are yet to be determined, it is unlikely that the observed upregulation of amygdalar OTR and plasma OT levels to reflect the acute effects of the drug since Sarnyai et al, 1992 has previously reported no effects of acute cocaine (another psychostimulant drug) on oxytocin content in plasma and amygdala. In support, acute doses of methamphetamine did not alter plasma OT levels in healthy adults (Bershad et al, 2015). In contrast to the normalized levels of plasma OT and amygdalar OTR binding following methamphetamine abstinence,…”

Alcohol acutely enhances decoding of positive emotions and emotional concern for positive stimuli and facilitates the viewing of sexual images

“…As expected (Bershad et al 2015), alcoholic beer produced positive subjective effects, including stimulation and happy and prosocial effects, such as increases in being talkative and open and the desire to be with others and not alone. These subjective effects likely contribute to the prosocial effects of alcohol.…”

“…A possible mediator is oxytocin, which is a key regulator of emotional and social behaviors (Heinrichs et al 2009). Although evidence suggests that chronic alcohol administration affects oxytocinergic function in the brain (Silva et al 2002), only two very small studies tested the acute effects of alcohol on circulating oxytocin (Bershad et al 2015;Mennella and Pepino 2006) and the findings were inconclusive. Oxytocin has been shown to facilitate the recognition of positive facial expressions (Di Simplicio et al 2009;Marsh et al 2010) and enhance emotional empathy (Hurlemann et al 2010).…”

“…An intravenous catheter was inserted for blood sampling, and baseline subjective effect measurements were performed. The participants were then asked to drink beer (alcoholic or non-alcoholic) over 15 min, and tests were performed starting 30 min after the start of beer intake when maximal effects were expected (Bershad et al 2015). We used a low-to-moderate dose of alcohol that sought to achieve a BAC of 0.4 g/L, which was associated with alterations in emotion recognition in some previous studies but not expected to result in nonspecific performance deficits (Attwood et al 2009a).…”

“…Visual analog scales (VASs; (Attwood et al 2009a;Bershad et al 2015;Hysek et al 2012) were used to assess the subjective effects of alcohol, including feeling "any effect," "stimulated," "happy," "talkative," "open," "be with others," and "be alone," before and 30, 70, and 95 min after beer administration. The VASs were presented as 100 mm horizontal lines that were marked ''not at all'' on the left and ''extremely'' on the right.…”