Ecstasy really does unleash the love hormone

http://www.newscientist.com/article/dn11530-ecstasy-really-does-unleash-the-love-hormone.htm

Ecstasy really does unleash the love hormone

04 April 2007
NewScientist
Emma Young

Clubbers who take the "love drug" ecstasy really might be "loved up".Studies in rats suggest the drug causes a brain surge of oxytocin - thehormone that helps bond couples, as well as mothers to their babies.Earlier research found increased oxytocin in the blood of people who hadtaken ecstasy. However, many drugs increase blood oxytocin withoutraising it in the brain - something thought necessary for any"pro-social" effects.Iain McGregor at the University of Sydney in Australia, and hiscolleagues studied the effects of ecstasy in rats, which, like people,become more sociable on the drug. "It's very characteristic behaviour.They lie next to each other and chill out," McGregor says.The team gave the rats the equivalent of two to three ecstasy tablets inan adult human and found that the drug activated oxytocin-containingneurons in an area of their brains called the hypothalamus. When theygave the rats a drug that blocked brain receptors for oxytocin, theincreased sociability almost disappeared.Why it didn't disappear entirely isn't clear. It could be that the doseof the receptor blocker was too low, or that other brain chemicals, suchas dopamine, are also involved in triggering the sociable behaviour,McGregor says."Sensual, not sexual"The finding ties in with reports from people on ecstasy about how theyfeel, McGregor points out. Rodent studies have shown a massive surge ofoxytocin after orgasm in males. "It's interesting that guys on ecstasyfeel more sensual than sexual," McGregor says. "It could be that raisingoxytocin levels puts them in that sort of post-orgasmic state wherethey're actually not very good at performing sexually but they feelreally good about the person they're with."McGregor's team now plan to investigate the levels of oxytocin in rats'brains after they've taken MDMA, and to see which parts of the brain inparticular are affected.They suspect that the oxytocin release might be implicated not only inthe pro-social effects of ecstasy but also in the reinforcing effects.There is much research to be done on how drugs of abuse affect oxytocinin the brain, says McGregor. "What we know at the moment could bewritten on the back of a postage stamp."--------------http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=17383105&query_hl=2&itool=pubmed_docsumNeuroscience. 2007 Mar 22A role for oxytocin and 5-HT(1A) receptors in the prosocial effects of3,4 methylenedioxymethamphetamine ("ecstasy").Thompson MR, Callaghan PD, Hunt GE, Cornish JL, McGregor IS.The drug 3,4 methylenedioxymethamphetamine (MDMA; ecstasy) has a widelydocumented ability to increase feelings of love and closeness towardothers. The present study investigated whether oxytocin, a neuropeptideinvolved in affiliative behavior, may play a role in this effect.A moderate (5 mg/kg, i.p.) dose of MDMA increased social interaction inmale Wistar rats, primarily by increasing the amount of time rats spentlying adjacent to each other.MDMA (5 mg/kg) activated oxytocin-containing neurons in the supraopticand paraventricular nuclei of the hypothalamus, as shown by Fosimmunohistochemistry.MDMA (5 mg/kg i.p.) also increased plasma oxytocin levels and thiseffect was prevented by pre-treatment with the 5-HT(1A) antagonist WAY100,635 (1 mg/kg i.p.).The oxytocin receptor antagonist tocinoic acid (20 mug, i.c.v.) had noeffect on social behavior when given alone but significantly attenuatedthe facilitation of social interaction produced by MDMA (5 mg/kg).The 5-HT(1A) agonist 8-hydroxy-2-(di-n-propylamino)-tetraline)(8-OH-DPAT, 0.25 mg/kg, i.p.) increased social behavior in a similar wayto MDMA and this effect was also significantly attenuated by tocinoicacid.Taken together, these results suggest that oxytocin release, stimulatedby MDMA through 5-HT(1A) receptors, may play a key role in the prosocialeffects of MDMA and underlie some of the reinforcing effects of thedrug.