Some science behind the scenes

Oxytocin

Oxytocin is an endogenous chemical that binds to oxytocin receptors.  It is a chemical that is released during love making,  sexual arousal and childbirth.  It has its own receptors in the brain, the spinal cord and in the genital organs.  OT receptors have also been identified in the kidney, heart, thymus, pancreas, and adipocytes.

It is generally released from the pituitary gland into the blood from where it travels via the blood stream to the rest of the body.  OT receptors are found in Leydig cells, also known as interstitial cells of Leydig, in the testicles.  And it has been shown that these have the capacity to produce oxytocin ‘de novo’ – by themselves.  The same things appears to happen with women, except it is the corpora lutea in the ovaries that does the work. Furthermore the heart can also produce oxytocin…..

The oxytocin receptor system: structure, function, and regulation - Gimpl G  Fahrenholz F. ; Institut für Biochemie, Johannes Gutenberg Universität, Mainz, Germany.

…. oxytocin (OT) and OT-like hormones facilitate reproduction in all vertebrates at several levels. The major site of OT gene expression is the magnocellular neurons of the hypothalamic paraventricular and supraoptic nuclei.  …. OT is also synthesized in peripheral tissues, e.g.,

  • uterus,
  • placenta,
  • amnion,
  • corpus luteum,
  • testis,
  • and heart.

Overall, the regulation by gonadal and adrenal steroids is one of the most remarkable features of the OT system and is, unfortunately, the least understood. One has to conclude that the physiological regulation of the OT system will remain puzzling as long as the molecular mechanisms of genomic and nongenomic actions of steroids have not been clarified.

PMID: 11274341

and it needs cholesterol and magnesium to be produced

The oxytocin receptor system: structure, function, and regulation - Gimpl G  Fahrenholz F. ; Institut für Biochemie, Johannes Gutenberg Universität, Mainz, Germany.

The OT receptor is a typical class I G protein-coupled receptor … The high-affinity receptor state requires both Mg(2+) and cholesterol, which probably function as allosteric modulators.

PMID:  11274341

Magnesium incidentally can be taken as a supplement and some supplemental magnesium users report an increase in vivid dreaming.  Some good sources of magnesium in foods include  - green vegetables such as spinach [because of the abundance of chlorophyll molecules which contain the ion], nuts (especially cashews and almonds), seeds, dark chocolate, roasted soybeans, bran, and some whole grains.

Oxytocin has a key role to play in quite a number of extremely key human functions:

  • Female reproduction – Oxytocin is released in large amounts after distension of the cervix and uterus during labor  and after stimulation of the nipples, facilitating birth and breastfeeding
  • Arousal .  It is responsible for a man’s erection as it relaxes [via an interaction with adenosine and its receptors] the smooth muscles of the penis.  The penis is normally held ‘flaccid’ or limp by means of contraction of the muscles, by relaxation the penis becomes erect.  Another hormone prolactin which is released on orgasm is responsible for the penis becoming limp.  If there is no orgasm clearly any form of sexual stimulation will simply increase the reserves of this hormone.  This is equally true of women in that the same two hormones are at play
  • Contentment - Oxytocin evokes feelings of contentment, reductions in anxiety, and feelings of calmness and security
  • Human bonding and attachment - many studies have already shown a correlation of oxytocin with human bonding, adult attachment and maternal bonding.  For this reason, it is sometimes referred to as the "love hormone". 
  • Envy – once the human bond has been formed, it also appears there is a knock on effect in inducing envy and jealousy
  • Trust and decrease of fear.  Oxytocin inhibits  controlling type behaviour, fear, and anxiety and thus, for example,  also has an effect on the quality of an orgasm, as trust in the partner allows the orgasm to occur.  For example, experimental subjects given nasally administered oxytocin displayed "the highest level of trust" twice as often as the control group. Subjects who were told that they were interacting with a computer showed no such reaction, leading to the conclusion that oxytocin was not merely affecting risk-aversion.
  • Generosity – Oxytocin affects the function of  generosity by increasing empathy during perspective taking. In a neuroeconomics experiment, intranasal oxytocin increased generosity in the Ultimatum Game by 80% but had no effect in the Dictator Game that measured altruism.
  •  Learning and memory - functions are impaired by centrally administered oxytocin. Also, systemic oxytocin administration can impair memory retrieval in certain aversive memory tasks. BUT, oxytocin does seem to facilitate learning and memory specifically for social information. Healthy males administered intranasal oxytocin showed improved memory for human faces, particularly happy faces.They also showed improved recognition for positive social cues over threatening social cues
  • Empathy in healthy males has been shown to be increased after intranasal oxytocin.  This is most likely due to the effect of oxytocin in enhancing eye gaze. “ There is some discussion about which aspect of empathy oxytocin might alter, for example cognitive vs emotional empathy”.

Oxytocin also affects the GABA receptor switching it from excitatory to an inhibitory state.

Vasopressin and oxytocin excite MCH neurons, but not other lateral hypothalamic GABA neurons - Yao Y,  Fu LY,  Zhang X,  van den Pol AN; Yale Univ Sch of Med.

Neurons that synthesize melanin concentrating hormone (MCH) …. regulate energy homeostasis, modulate water intake, and influence anxiety, stress, and social interaction. Similarly, vasopressin and oxytocin can influence the same behaviors and states, suggesting that these neuropeptides may exert part of their effect by modulating MCH neurons. …………… [the data from this study] suggest that vasopressin or oxytocin exert a minimal effect on most GABA neurons in the lateral hypothalamus, but exert a robust excitatory effect on presumptive GABA cells that contain MCH. Thus, some of the central actions of vasopressin and oxytocin may be mediated through MCH cells.

Another interesting though perhaps less important finding [since this is not a site about drugs]  is that MDMA works via oxytocin receptors.

Increased oxytocin concentrations and prosocial feelings in humans after ecstasy (3,4-methylenedioxymethamphetamine) administration - Dumont GJ et al

Unit for Clinical Psychopharmacology and Neuropsychiatry, Department of Psychiatry, Radboud University Nijmegen Medical Centre, 966, PO Box 9101, Nijmegen NL-6500 HB, The Netherlands.

MDMA (3,4-methylenedioxymethamphetamine or "ecstasy") is a recreationally used drug with remarkable and characteristic prosocial effects. In spite of abundant attention in the scientific literature, the mechanism of its prosocial effects has not been elucidated in humans.

Recently, research in animals has suggested that the neuropeptide oxytocin may induce these effects. In a double blind, randomized, crossover, and placebo-controlled study in 15 healthy volunteers we assessed blood oxytocin and MDMA concentrations and subjective prosocial effects after oral administration of 100 mg MDMA or placebo.

MDMA induced a robust increase of blood oxytocin concentrations and an increase of subjective prosocial feelings. Within subjects, the variations in these feelings were significantly and positively correlated with variation in oxytocin levels, and the correlations between these feelings and oxytocin were significantly stronger than those between these feelings and blood MDMA levels.

MDMA induces oxytocin release in humans, which may be involved in the characteristic prosocial effects of ecstasy.

PMID: 19562632

Furthermore, one of the more unpleasant knock on effects of the kappa opioid receptor is to inhibit the secretion of peripheral Oxytocin.  Out of interest you may like to know that the following work as agonists at this receptor

Dextromethorphan, Ibogaine, Menthol, Methadone, Morphine, Nalbuphine, Noribogaine,  Salvinorin A, and Salvorin B. The natural agonist mentha is found in numerous species of mint, (including peppermint, spearmint, and watermint), but it is only a very weak k-opioid receptor agonist.

They have done experiments on babies -  ‘fetal subjects’ [!]  - which show that oxytocin has a very distinct role to play when the baby is born.  The action on the GABA receptor serves to ‘silence the fetal brain for the period of delivery and reduces its vulnerability to hypoxic damage’.  Eureka – it stills the reasoning mind!!

You may think this is just the action on a baby at birth, but in fact it has found to be generally true.  Learning and memory functions are impaired by centrally administered oxytocin.  To quotesystemic oxytocin administration can impair memory retrieval in certain aversive memory tasks”, so it stills the reasoning mind – the one we have to use when we are fulfilling the ego and trying to work things out.  But it doesn’t still the mind for the important things in life “Interestingly, healthy males administered intranasal oxytocin show improved memory for human faces, particularly happy faces”.

So we don’t go gaga – we become innocents – trusting happy, children with the capacity to have a very extreme spiritual experience – as long as the oxytocin can be maintained at a steady state for long enough.

Observations

For iPad/iPhone users: tap letter twice to get list of items.