The brain, sex, and opiates
Well now if that title doesn't get your interested, I'm not sure what will. As the subject suggests I'm trying to write today about some of the research about the brain, sex, and opiates. There is a relationship among the 3 things. I'm going to start with a story from my life.
This is one of those stories of a rather personal nature but it's also a good introduction to my own exploration of how the brain responds to sexual partners. I once knew a woman that I was very deeply in love with. On two occasions while having sex with her the act of climax was so intense for me that I reached a state that I didn't know was possible. It was almost like a state of being blacked out and being somewhat paralyzed. The pleasure was so intense that I didn't feel like I could move for some time.
At some point in time later I came across the story about research into the brain and opiates. The question that had been asked was why does the brain even have attachment points for opiates? And what the research revealed was that the brain produces substances that are opiate-like. No I'm not even going to say but I'm an expert on these chemicals. There's a variety of them and they are known as the pleasure chemicals. Some of them increase just simply from a hug, some of them increase when a man sees an attractive woman.
Sometime after this I was talking to a psychologist about this event, this extremely pleasurable event. I expressed that I wondered what the addictive effect was of this very strong release of whatever chemicals that causes extreme pleasure. I don't think she was aware of the most recent research and she seemed rather surprised that I would suggest this. But she did give me a name for what those chemicals that the body naturally produces. They are called endogenous opiates.
To give you just a little bit more background into the endogenous opiate system I refer to the research paper "Opioid system and human emotions," by Lauri Nummenmaa, Lauri Tuominen, published in the British Journal of Pharmacology, volume 175, issue 14:
"Emotions are states of vigilant readiness that guide human and animal behaviour during survival-salient situations. Categorical models of emotions posit neurally and physiologically distinct basic human emotions (anger, fear, disgust, happiness, sadness and surprise) that govern different survival functions. Opioid receptors are expressed abundantly in the mammalian emotion circuit, and the opioid system modulates a variety of functions related to arousal and motivation. Yet, its specific contribution to different basic emotions has remained poorly understood. Here, we review how the endogenous opioid system and particularly the μ receptor contribute to emotional processing in humans. Activation of the endogenous opioid system is consistently associated with both pleasant and unpleasant emotions. In general, exogenous opioid agonists facilitate approach-oriented emotions (anger, pleasure) and inhibit avoidance-oriented emotions (fear, sadness). Opioids also modulate social bonding and affiliative behaviour, and prolonged opioid abuse may render both social bonding and emotion recognition circuits dysfunctional. However, there is no clear evidence that the opioid system is able to affect the emotions associated with surprise and disgust. Taken together, the opioid systems contribute to a wide array of positive and negative emotions through their general ability to modulate the approach versus avoidance motivation associated with specific emotions. Because of the protective effects of opioid system-mediated prosociality and positive mood, the opioid system may constitute an important factor contributing to psychological and psychosomatic resilience."
Both of these books I think are really excellent reads when it comes to understanding our humanity. Now that I have given you just a little bit about the endogenous opiate system, I’d like to give you some quotes from “Why We Love:”
From the preface:
"Romantic love, I believe, is one of three primordial brain networks that evolved to direct mating and reproduction. Lust, the craving for sexual gratification, emerged to motivate our ancestors to seek sexual union with almost any partner. Romantic love, the elation and obsession of “being in love,” enabled them to focus their courtship attentions on a single individual at a time, thereby conserving precious mating time and energy. And male-female attachment, the feeling of calm, peace, and security one often has for a long-term mate, evolved to motivate our ancestors to love this partner long enough to rear their young together."
From pages 52 to 55:
Rock On, Sweet Dopamine
Take dopamine. Elevated levels of dopamine in the brain produce extremely focussed attention,2 as well as unwavering motivation and goal-directed behaviors.3 These are central characteristics of romantic love. Lovers intensely focus on the beloved, often to the exclusion of all around them. Indeed, they concentrate so relentlessly on the positive qualities of the adored one that they easily overlook his or her negative traits;4 they even dote on specific events and objects shared with this sweetheart. Besotted lovers also regard the beloved as novel and unique. And dopamine has been associated with learning about novel stimuli.5 Central to romantic love is the lover’s preference for the beloved. As you recall from chapter two, among prairie voles, this favoritism is associated with heightened levels of dopamine in specific brain regions. And it is not a leap of logic to suggest that if dopamine is associated with mate preference in prairie voles, it can play a role in partiality in people. As you recall, all mammals have basically the same brain machinery, although size, shape, and placement of brain parts definitely vary.6 Ecstasy is another outstanding trait of lovers. This, too, appears to be associated with dopamine. Elevated concentrations of dopamine in the brain produce exhilaration, as well as many of the other feelings that lovers report—including increased energy, hyperactivity, sleeplessness, loss of appetite, trembling, a pounding heart, accelerated breathing, and sometimes mania, anxiety, or fear.7 Dopamine involvement may even explain why love-stricken men and women become so dependent on their romantic relationship and why they crave emotional union with their beloved. Dependency and craving are symptoms of addiction—and all of the major addictions are associated with elevated levels of dopamine.8 Is romantic love an addiction? Yes; I think it is—a blissful dependency when one’s love is returned, a painful, sorrowful, and often destructive craving when one’s love is spurned. In fact, dopamine may fuel the frantic effort a lover musters when he/she feels the love affair is in jeopardy. When a reward is delayed, dopamine-producing cells in the brain increase their work, pumping out more of this natural stimulant to energize the brain, focus attention, and drive the pursuer to strive even harder to acquire a reward: in this case, winning one’s sweetheart.9 Dopamine, thy name is persistence. Even the craving for sex with the beloved may be indirectly related to elevated levels of dopamine. As dopamine increases in the brain, it often drives up levels of testosterone, the hormone of sexual desire. Norepinephrine’s High Norepinephrine, a chemical derived from dopamine, may also contribute to the lover’s high. The effects of norepinephrine are varied, depending on the part of the brain it activates. Nevertheless, increasing levels of this stimulant generally produce exhilaration, excessive energy, sleeplessness, and loss of appetite—some of the basic characteristics of romantic love. Increasing levels of norepinephrine could also help explain why the lover can remember the smallest details of the beloved’s actions and cherished moments spent together. This liquor is associated with increased memory for new stimuli.10 A third chemical may also be involved in that “irresistible” feeling of magic Homer spoke of: serotonin. Serotonin A striking symptom of romantic love is incessant thinking about the beloved. Lovers cannot turn off their racing thoughts. Indeed, this single aspect of being in love is so intense that I use it as the litmus test of romantic passion. The first thing I ask anyone who tells me they are “in love” is, “What percentage of your waking hours do you think about your sweetheart?” Many say “over 90 percent.” Some bashfully admit they never stop thinking about “him” or “her.” Lovers are obsessed. And doctors who treat individuals with most forms of obsessive-compulsive disorder prescribe SSRIs (selective serotonin reuptake inhibitors) such as Prozac or Zoloft, substances that elevate levels of serotonin in the brain.11 So I came to suspect that the lover’s persistent, involuntary, irresistible ruminations about a sweetheart might be associated with low levels of some type (there are at least fourteen variations) of this chemical compound.12 There is some support for my reasoning. In 1999, scientists in Italy studied sixty individuals: twenty were men and women who had fallen in love in the previous six months; twenty others suffered from unmedicated obsessive-compulsive disorder (OCD); twenty more were normal, healthy individuals who were not in love and were used as controls. Both the in-love participants and those suffering from OCD were found to have significantly lower levels of serotonin than did the controls.13 These scientists examined serotonin levels in components of the blood, however, rather than the brain. Until scientists document the activity of serotonin in specific brain regions, we cannot be sure of the role of serotonin in romantic love. Nevertheless, this experiment has established, for the first time, a possible connection between romantic love and low levels of bodily serotonin. All those countless hours when your mind races like a mouse upon a treadmill may be associated with reduced levels of serotonin coursing through the highways of the brain. And as a love affair intensifies, this irresistible, obsessive thinking can increase—due to a negative relationship between serotonin and its relatives, dopamine and norepinephrine. As levels of dopamine and norepinephrine climb, they can cause serotonin levels to plummet.14 This could explain why a lover’s increasing romantic ecstasy actually intensifies the compulsion to daydream, fantasize, muse, ponder, obsess about a romantic partner."
Notes from the above section:
2. Horvitz et al. 1997; Schultz et al. 1997; Schultz 2000.
3. Kiyatkin 1995; Salamone 1996; Robbins and Everitt 1996; Wise 1996; Luciana et al. 1998.
4. Murray and Holmes 1997.
5. Horvitz et al. 1997; Schultz et al. 1997; Schultz 2000.
6. Pfaff 1999; Panksepp 1998.
7. Wise 1988; Colle and Wise 1988; Post, Weiss, and Pert 1988; Kruk and Pycock 1991; Volkow et al. 1997.
8. Abbott 2002; Schultz et al. 1997; Wise 1989, 1996, 1988; Robbins and Everitt 1996.
9. Schultz 2000; Martin-Soelch et al. 2001.
10. Griffin and Taylor 1995.
11. Flament et al. 1985; Hollander et al. 1988; Thoren et al. 1980.
12. H. Fisher 1998.
13. Marazziti et al. 1999.
14. Luciana, Collins, and Depue 1998.