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Unveiling the weirdest physiological substance.

trailblazerPosted for Everyone to comment on, 5 years ago15 min read

“The human body can only bear a maximum of 45dels of pain, however, the pain associated with child delivery is about 57dels of pain, this is equivalent to fracturing twenty bones”.

I’ve been a victim of bone fracture and this popular statistics would thrill anyone who knows what it means to dislocate a Joint which is very less painful than bone fracture, ‘equivalent to fracturing twenty one bones’!, really insane. Fortunately this claim is falsified as there’s no such unit as ‘del’ and moreover, the intensity of the pain of child delivery is dependent on many factors and varies from one mother to another and hence doesn’t have any standard figure or range of figures which quantifies it...at least not in dels and not equivalent to fracturing twenty bones!.

Nevertheless, the pain associated with child delivery is one the highest pain anyone can take and in the real sense, the above claim is not completely a hoax as labour is the highest physiologic pain known, only certain very few state of physical injury provides pains which are comparable to it. I wouldn’t go back to the source of such pain if I were to be a woman, even on my postings to the maternity ward, about 60% of the mothers in active labor swears unconsciously never to get pregnant again, surprisingly when asked some hours after their delivery if they’d love to have another baby, the reply is always a loud ‘yes’, and the doctors will always laugh at that.

Elsewhere and far away from gynecology, a team of neuroscientists led by Thomas Baumgartner at the university of Zurich, Switzerland monitored the nervous activity of fourty-nine (49) men while they participated in a trust and betrayal game; the fourty-nine (49) men were divided into groups of uneven numbers and each group were given a reasonable amount of money which they’d give to an investor who would increase the amount through profits or betray them and keep the whole amount to himself. The groups were separated and while one group got a whiff of oxytocin through a nasal spray of inhalable oxytocin, the other group received a placebo(unreal analogue) spray. The group administered with a real oxytocin spray entrusted the investor with the whole money which they received while the group who were administered with a placebo spray reduced the amount of money which they handed over to the investor.

Meet the culprit



3D structure of oxytocin . Source:Wikimedia - CC BY-SA 3.0.

Oxytocin is a nonapeptide hormone and neurotransmitter of 1007Da (1.007Kda) molecular weight produced by the paraventricular nucleus of the hypothalamus and released by the posterior pituitary. Henry Dale in 1906 discovered oxytocin, however it’s molecular structure was determined 46years later in 1952.

The nine peptides of oxytocin are arranged thus:Cystein–Tyrosine–isoleucine–glutamine–asparagine–cystein–proline–leucine–glycine–primary amide(NH2).



Structure of oxytocin . Source:wikimedia - CC BY-SA 3.0.

The C-terminus of oxytocin has been converted to a primary amide and a disulphide bond joins the cysteine moieties. The biologically active form of oxytocin is it’s oxidized form known as octapeptide oxytocin disulphide but it also exists in a non-cyclic reduced state as a dithiol nonapeptide known as oxytociene which acts as a free radical scavenger and reoxidizes to oxytocin after donating an electron to a free radical.

Structurally, oxytocin is similar to vasopressin a nonapeptide hormone with a single disulphide bridge also released by the posterior pituitary gland, the major structural difference between the two hormones being the replacement of isoleucine with phenylalanine at position 3 and replacement of leucine with arginine at position 8 in vasopressin, the magnocellular neurosecretory cells which produces oxytocin are located adjacent to vasopressin producing magnocellular neurosecretory cells.

The biochemistry of oxytocin is relatively uniform in humans, however, a variant form of oxytocin has been discovered in primates and lower mammals, due to a single in-frame mutation of the OXT gene which codes for oxytocin in these animals.Different disciplines has different orientation of oxytocin, this is due to the versatility of this hormone, though there exists a link between these actions.

Oxytocin in Gynaecology and Reproduction

For a gynaecologist, oxytocin plays a central role in parturition and lactation via the oxytocin receptors (OTR), oxytocin regulates a large number of reproduction related processes in every specie, unlike the major sex hormone, oxytocin is found in both male and female sexes, anyways, it’s actions are more pronounced in the females especially during parturition and lactation.

Contraction of the uterine muscles is very vital in expelling the baby during labour and also in milk release and ejection from glandular epithelium of the breast, the bulk of these actions is through oxytocin activity via the oxytocin receptors.



Evolutionary tree of the oxytocin, vasotocin, mesotocin and isotocin receptors and their ligands. Source:Wikimedia - CC BY-SA 3.0.

The oxytocin receptor is a rhodopsin-type receptor of the G-coupled receptor family, it stimulates the contraction of the myometrium by elevating the intracellular calcium and sensitisation of the muscular contraction apparatus to calcium, sensitisation of the contractile apparatus to calcium ion is the most relevant action of oxytocin in child delivery. Oxytocin also has a contraceptive activity, this is due to the stimulation of oxytocin during breastfeeding, as the baby sucks on the nipples. This released oxytocin causes contraction of the uterine muscles, lactating mothers are as a result unable to conceive, this also accounts for the mild pain uterine contractions felt by lactating mothers.

Oxytocin receptor activity has been the major case study in experiments geared towards the management of dysfunctional and premature labour as drugs which activates oxytocin receptors would be functional in management of dysfunctional labour, inhibition of oxytocin receptors reduces the force which tends to expel the baby from the womb, premature labour would be efficiently managed via these means. The goal is to regulate oxytocin via local changes in oxytocin concentration, regulation of changes in oxytocin receptor expression and desensitization. Estradiol, an estrogen is a potent agent in the regulation of oxytocin concentration, a single dose of estradiol is sufficient enough to increase the expression of oxytocin receptors.

In males, the oxytocin has endocrine and paracrine roles in male reproduction, the release of oxytocin from neurohypophysis into the systemic circulation during sexual intercourse stimulates the contraction of the reproductive tract, aiding the release of sperm, via it’s paracrine action, it also stimulates the contraction of the prostrate gland, epididymis and seminiferous tubules, this aids the expulsion of sperm from the penis and sperm transport through the female genital tract is also aided by the contraction action of oxytocin. Even though these contractions are taking place at different parts, the mechanism is basically the same.

Oxytocin in psychology



oxytocin and vasopressin mediates the psychological feeling of attachment . Source:Wikimedia - CC BY-SA 3.0.

Apart from being a sex hormone, oxytocin is also a potent neuropeptide and plays a role in social bonding, love, trust, fear, empathy and generosity. Many psychological activities can be traced down to oxytocin and oxytocin is becoming a very special focus for psychologists.

To give an explanation for the introductory stories

During pregnancy and especially during labour, oxytocin production and release is greatly stimulated, it’s effect in child delivery have already been explained. Why mothers still has enough courage to conceive again would puzzle anyone who really experienced the pain they had gone through on previous delivery, in fact women tend to forget the pains of labour few hours after delivery, now this is not due to the joy of a new baby as you would think, as even on still birth, this enthusiasm to conceive again is relatively the same in most women. This is due to nervous transmission by oxytocin whose production is higher in the brain than in any other part of the body.

Better explanation of the psychological effect of oxytocin is provided by Thomas Baumgartner’s trust and betrayal game experiment. A study of the functional magnetic resonance imaging of the men who received oxytocin spray showed a drop in nervous activity in the amygdala.



The amygdala . Source:Wikimedia - CC BY-SA 3.0.
The amygdala is a set of almond-shaped neurons located in the medial temporal lobe of the brain, this structure is linked to responses to fear and pleasure, it is the most sexually dimorphic structure and is found to be shrinked in individuals with little or no sexual urge, it forms a part of the limbic system and has shown to play a key role in processing of emotions and psychological disorders such as fear, anxiety, autism, depression and phobias are thought to be linked to abnormal functioning of the amygdala due to neurotransmitter imbalance, damage or developmental problems.

In Baumgartner’s experiment, this drop in activity in the amygdala is shown to be an explanation of the huge trust which existed between the men who received the oxytocin spray and the investor.



In Baumgartner's experiment, diminished activity in the dorsal stratum was also experienced Source:wikimedia - CC BY-SA 3.0.

Diminished activity was also experienced in the dorsal stratum ( the region associated with learning from mistakes) in the men administered with oxytocin. Surprisingly, when this game was repeated with a computer as the investor, the psychological reactions didn’t take place amidst oxytocin administration, this showed a human-enhanced action in the activity of oxytocin.

Oxytocin hence creates a link between human medicine and psychology, continued research on oxytocin has increased the general understanding of the mode of action of the hormone in biochemical activities of the reproductive and nervous system. This has led to an increased application of oxytocin in therapeutic procedures and many more speculated and experimented possible applications of oxytocin.

Let’s take a look at some applications of oxytocin:

Treatment of frontotemporal dementia: According to a new study, Bi-daily administration oxytocin for a week to a dementia patient showed preliminary signs of improvement in symptoms of apathy and loss of empathy in frontotemporal dementia patients.

Dementia is a general term that describes a group of symptoms associated with a decline in memory and other thinking skills to the extent that ones ability to perform normal daily activities are affected. It is usually associated with loss of short-term memory, individual might be able to remember their names, age and parents but may be unable to remember the last person they spoke to and the issues they discussed with such persons.



Histopathologic image of senile plaques seen in the cerebral cortex in a patient with presenile onset of Alzheimer disease, frontotemporal dementia is the most common cause of this condition. Source:Wikimedia - CC BY-SA 3.0.
Frontotemporal dementia usually starts off between the age 50-60 years and is the most common cause of presenile dementia with loss of empathy being the most conspicuous symptom. Frontotemporal dementia patients tends to be self centred and grow unappreciative of the efforts of other family members or friends, it is also associated with emotional blunting and a decline social behaviors. Oxytocin as an mediators of social behaviors and enhancer of empathy was tested out on some patients of frontotemporal dementia and the out come of this experiment was encouraging.

For the randomized, double-blind study, 23 patients with behavioral variant frontotemporal dementia or semantic dementia were randomly assigned to placebo or one of three doses of intranasal oxytocin (24, 48, or 72 IU) administered twice daily for 1 week.
Results showed that all three doses of intranasal oxytocin were safe and well tolerated.
medscape

Good patient-caregiver relationship was also revealed to be very essential in this experiment, this is due to the human-human relationship dependent natural of oxytocin action. Presently, hypersexuality is the only side effect associated with this experiment as some of the patients developed an increased sexual urge, many frontotemporal dementia patients may already be hypersexual and this is the main cause of worry an increase in the already existing hypersexuality may be detrimental.

Improvement of social and group behavior:

Dubbed the ‘Love hormone’ oxytocin is prominent for it’s ability to improve trust and attachment between people. Anti-social individuals are characterized by the fear to mix up with others due to distrust, fear of a feeling of ‘not belonging’ to the group in question. Experiments in laboratory mice has shown that oxytocin reduces fear by activating the inhibitory circuit in the amygdala, in humans, oxytocin has been shown to inhibiting the amygdala which is thought to be concerned with the feeling fear.



Anti-social individuals feels scared to engage in group conversation. Source:Wikimedia - CC BY-SA 3.0.
However other results of oxytocin administration has shown otherwise, individuals who have received an intranasal administration of oxytocin have shown an increase in envy and are prone to the expression of facial disgust faster than people who didn’t . The effect of oxytocin in improving social behaviors is thus obscured as even though it inhibits fear and the feeling of non-attachement, it also possess a threat of anti-socialism as envy and disgust are anti social features, experiments are ongoing in an attempt to unravel the principle behind this varied action of the same hormone.

Military operations: Being in the military could be discouraging, extremely discouraging, major cause of the discouragement being the fear arising from the thought of the perils one goes through as a soldier, this plays a role in military assignments as the feeling of distrust and intense are major factor which determines the extent any military team.



Administration of intranasal oxytocin may increase courage in soldiers. Source:Wikimedia - CC BY-SA 3.0.
Military guidance and counselling schemes are centred on eradicating fear. This is where oxytocin action steps in. The inhibitory action on the fear centre of the amygdala could prove functional in getting rid of the fear felt by soldiers through the administration of intranasal oxytocin. Side effects and appropriate dosage should also be keep in mind during the administration of intranasal oxytocin for the management of emotional issues as regards military operations

Management of personality disorders: Personality disorders are set of abnormal personal attitude in an individual which presents the individual as not ideal in terms of attitude, this may include depression amongst other already anti mentioned, the feeling of fear and anxiety and lack of trust may present an individual with behaviors of anti-socialism and subsequently the individuals' attempt and struggle to live with these feelings only results in personality disorders. Administration of oxytocin would aid the individual to cope with these feelings, oxytocin have proven to produce anti-depressant like effects in experimental animal models and it’s deficit my account for depression in humans.

Many wonderful applications of oxytocin exists, however, the extremity of these actions may also have a dark side to it, oxytocin mechanism of action is actually more complex than it is, administration of oxytocin to improve acquaintance with a specific group may lead to group prejudice as the individual becomes more attached to the group and develops disgust for other groups, anyways, the research on oxytocin continues to reveal the complexity of the human biology, biochemistry and psychology.

Creation of superhuman with super courage abilities may also be made possible by the development of oxytocin action, things may go wrong via this experiment. Manipulation of human attachment and trust can also be done through oxytocin administration and maybe future ‘love portions’ will contain an amount of oxytocin.

Thanks for reading through

References

  1. oxytocin~wikipedia

  2. oxytocin~psychologytoday

  3. Amygdala~sciencedaily

  4. Oxytocin: Its Mechanism of Action and Receptor Signalling in the Myometrium~researchgate

  5. The Neurochemistry of Forgiving and Forgetting~sciencemag

  6. what is dementia?

  7. Oxytocin May Help Frontotemporal Dementia~sciencemag

  8. Oxytocin helps to better overcome fear~sciencedaily

  9. Oxytocin—its role in male reproduction and new potential therapeutic uses~academic

  10. Multiple mechanisms involved in oxytocin-induced modulation of myometrial contractility~nature


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