On a Possible Psychophysiology of the Yogic Chakra System (Part 2)

Dr. S.M. Roney-Dougal

The thyroid gland: vishuddhi chakra

According to Satyananda (1972b), vishuddhi chakra is located in the throat and is the centre of 'the nectar of immortality'. It is connected with the sense of hearing and thus with the ears, and of course with the vocal cords and with self-expression.

The thyroid makes thyroxine, which regulates the metabolic rate of the body, i.e. it controls how fast the body runs: an overactive thyroid means that the heart beats fast, one becomes thin, sexual desire increases, and the mind works overtime; whilst an underactive thyroid has the opposite effect. Neurochemically, the thyroid is under the inhibitory control of the pineal gland, removal of the pineal resulting in thyroid enlargement and increased hormonal secretion rate. The pineal is also under feedback control by the glands which it influences. Pineal cells respond to thyroxine, the response being particularly strong at night.

Synthetic melatonin has the effect of inhibiting iodine uptake and the secretion of thyroxine, and, given at the correct times, can reproduce the daily and annual biological rhythms since iodine uptake naturally decreases during the night. Thus, evening injections of melatonin are more effective than morning ones, showing that the time of day when hormone supplementation is given is a significant factor, the influence of the circadian rhythm once again. (Johnson, 1982). The effect of synthetic melatonin on the secretion of thyroxine decreases after puberty.

The hypothalamus makes thyroid releasing hormone (TRH), which stimulates the pituitary to make thyrotropin (TSH), which stimulates the thyroid to make thyroxine.1 There is a circadian variation in human TSH levels, TSH beginning to rise several hours before the onset of sleep, reaching maximum levels between 11.00 p.m. and 4.00 a.m., declining gradually with a minimum at 11.00 a.m. People with hypothyroidism also show a seasonal variation and circadian changes in plasma TSH, which suggests that the circadian rhythm of TSH is not related to the negative feedback control exerted by thyroid hormones under normal conditions: serum thyroxine levels show maximum concentration in late morning and minimum concentration in early morning.

Sleep deprivation results in larger and broader TSH peaks. Pinealectomy does not result in changes in serum TSH or hypothalamic TRH content, nor does it produce alterations on the diurnal rhythms of hypothalamic TRH – so there is little firm evidence for significant interactions between melatonin and rhythmicity of TSH secretion, yet chronic melatonin treatment decreases pituitary TSH content and increases plasma TSH concentration.

TSH is, together with melatonin and the adrenals, involved in coping with long term stress. Alpha-adrenergic pathways play a role in the stimulatory control of TSH release. Circadian changes in cortisol levels follow an opposite pattern to those of TSH. Glucocorticoid administration has an inhibitory effect on TSH secretion and rhythmicity, but there does not seem to be a close relationship between the daily profiles of each hormone and abolition of the circulation rhythm of cortisol does not disrupt the TSH rhythm. Glucocorticoids inhibit TSH release, and so the circadian rhythm of TSH is abolished in patients with hypercortisolism (Johnson, 1982).

Stress is intimately connected with metabolic rate, heart rate, an overactive mind, and also with age as an older person cannot cope with stress as well as a younger person. Long term stress is very different from short term stress (which is dealt with by the adrenals) and it is interesting that ajna, vishuddhi and manipura are all concerned with stress – which also affects the heart – when the mind just won't stop going in circles around the problem (the beta-rhythm mental chatter), which is one of the worst aspects of long term stress. These are all the negative aspects of vishuddhi and we learn through meditation to overcome these aspects and so to become peaceful, still, calm and to live to a ripe old age, which is another way of saying that the thyroid is connected with immortality. Relaxation is the first step in meditation; slowing down, letting go, releasing the stress, stilling the endless internal chatter as is exemplified so well by the Chinese symbol of immortality, the tortoise; the slower you go, the longer you live. Yogic lore states that it is perfectly possible to regulate the functioning of the endocrine system, thus learning how to control one's metabolic rate. It is feasible that yogic exercises designed for the ajna chakra do physically regulate the pineal gland and so influence the functioning of the other endocrine organs.

The heart centre: anahata chakra

According to Satyananda (1972b), anahata chakra is concerned with will and with feeling, touch, the skin especially the hands, manifesting in such arts as painting, poetry and music, which are aspects of heart.

The thymus

As a result of the writings by Theosophists, many people consider that anahata chakra is connected with the thymus gland, which physiologically is most active in children and is concerned with the immune system. Recent research suggests that there is a connection between the pineal gland and the thymus because of its interaction with the immune system, as mentioned in the section on the pineal gland as command chakra. Functional connections between the immune and the neuroendocrine systems are being increasingly recognized. Thus stressful effects, distress, from psychological or neuro-endocrinological causes may adversely affect the immune system and vice versa.

Circadian synthesis and release of melatonin exerts an important immunomodulatory role, in that it appears to be a physiological up-regulator of the immune system and to operate via the endogenous opioid system on antigen activated cells. When given in the evening to mice it increases the primary antibody response to T-dependent antigens, buffers the depression of antibody production and thymus weight induced by the acute restraint of mice inoculated with sheep red blood cells, and confers resistance against injections of a virus, not by protecting the thymus cortex but because it enlarges the thymus medulla. The anti-stress action of melatonin appears to be antagonized by administration of the opioid antagonist naltrexone, suggesting that melatonin operates via the endogenous opioid system (EOS) even though the opioid system is not itself involved in the immunological effect of acute stress. When administered in the morning no effect on the immune system was found (Maestroni et al, 1989). Thus, it is possible to see melatonin as an anti-stress hormone since melatonin reverses the depression of antibody production induced by corticosterone in drinking water. Failure to cope with distress may be dependent on an exhausted EOS and melatonin may restore the EOS.

So there is some connection between the pineal and the thymus in animals, and yet whilst there is a certain link between keeping healthy and the normal concept of the emotional aspect of heart in our culture, there is another hormone connected with this region in humans which expresses heart emotion much more strongly: the hormone prolactin which is connected with lactation in the breasts.


I have noticed in my research into the pineal that melatonin is the off-switch for a hormone called prolactin which is made by the pituitary, is involved with pregnancy and stimulates lactation, and is implicated in manic-depression. Most of the research with prolactin has been with animals, but there has been some research with humans showing once again the link with the pineal gland.

In seasonally breeding species in which both hormones show a seasonal variation, melatonin mediates the influence of light on prolactin release. All ruminants (e.g. cows, sheep) show a marked seasonal fluctuation in plasma prolactin concentration, i.e. high in summer and low in winter, and certain animals become impregnated in autumn at the end of the long day light hours (Wurtman, 1979), this fluctuation being controlled by melatonin. This inhibition of prolactin secretion in ruminants inhibits implantation of the blastocyst during the winter, so that the foetus does not implant into the womb until spring time, even though mating and fertilization occurred in autumn.

Prolactin secretion in women is also controlled by the ovarian steroids, its level being modified by the fluctuating oestradiol levels of the menstrual cycle. Whilst few clinicians would accept a seasonal basis for reproduction in humans, older epidemiological data, and data more recently derived from conditions of borderline fertility, both support a seasonal change. The exact link to melatonin is as yet unestablished but seasonal changes in plasma melatonin have been described (Matthews, 1981) for women, but not for men. Martikuinen et al (1985) found peaks in both summer and winter, and Touitou et al (1984) found differences between young and old people (see vishuddhi chakra).

Webley (1988) worked with 11 young men intermittently over a 9 month period. He found that, like melatonin, prolactin shows a night time peak around 3–4.00 a.m. and that, whilst inter-individual variations are large, there are no changes in the amplitude of the peaks across the February, March and June samplings. This significant positive correlation between melatonin and prolactin concentrations is greatest at night and strongest in June. Melatonin concentrations decrease earlier than prolactin in the morning and increase before prolactin in the evening (see Figure 3 and Table 2).

Prolactin concentration increases with sleep. The dependence on sleep is independent of time of day, so night workers will make some of their prolactin during the day, but prolactin also shows a circadian pattern of high levels at night. There were inconsistent changes in the circadian pattern of melatonin for the individuals, which suggests that environmental factors other than the light/dark cycle can influence the circadian pattern in men, and as I am suggesting here, stress/relaxation is one of these factors – other factors may be sleep/activity pattern, different social cues and physical exertion.

Webley found that melatonin doses given both morning and evening stimulated a significant increase in prolactin concentrations. There is a diurnal rhythm in sensitivity to melatonin: melatonin given in the morning stimulates a constant increase in prolactin concentration across the sampling period, whereas in the evening a peak in prolactin was evident after 90–120 minutes.

This leads to the conclusion that it is possible that melatonin may control directly the nocturnal increase in prolactin, but in some cases if melatonin concentration is increased, prolactin concentration is decreased; for example, a decrease in melatonin by pinealectomy results in an increase in prolactin release and the nocturnal increase in prolactin is absent in a pinealectomised human who had no nocturnal increase in melatonin. The observed stimulation of prolactin after melatonin injection in the human is also at odds with the inhibition of prolactin release in seasonally breeding animals – this may be indicative of a difference between the response to acute and chronic melatonin administration as is also seen with thyroxine, or may be indicative of the different responses to the hormones between humans and animals. In rats acute administration of melatonin stimulates prolactin, whereas prolactin is inhibited with chronic melatonin. Melatonin can inhibit dopamine release from the rat hypothalamus, the degree of response showing circadian variation. Since dopamine is known to inhibit prolactin release, the influence of melatonin on prolactin may therefore be via a dopaminergic mechanism. Such a mechanism would provide a central site of action for melatonin on human reproduction (Webley, 1988).

Research by Allman (1998), and Ziegler (in press) suggests that in some male species prolactin changes in the fathers are elevated just prior to and following the birth of the offspring, in some cases just as high as their nursing mates. The most experienced fathers had the highest levels of prolactin, the paternal high prolactin level remaining for up to six weeks after birth (Motluk, 1998).

Like TRH, prolactin secretion during the day follows the opposite pattern to that of cortisol. Glucocorticoid administration reduces pituitary prolactin content and release as well as prolactin responses to TRH, but does not affect circadian rhythm.

Oestrogens stimulate prolactin secretion, so women have higher basal levels, particularly during reproductive years and pregnancy. There is a close parallel between plasma oestradiol and prolactin. Women have higher sleep-related prolactin elevations.

Further hypersecretion of prolactin and the related pituitary hormones, luteinising hormone (LH) and human growth hormone (HGH)2 may be associated with affective (mood) disorders such as manic depression and recurrent depression – here we see clearly the link between emotional, physical and psychological state of being through its disturbance. Further, dopamine antagonism is a feature of major tranquillizers which may cause high prolactin levels; dopamine neurotransmitter dysfunction is associated with schizophrenic disorder and Salvador (1988) considers that dopamine is the most important inhibitory regulator of prolactin and TSH synthesis.

I am suggesting that the hormones are the physical aspect of the chakras. Every hormone appears to have a physical component which affects the working of the body. They also appear to have an emotional component, and I am suggesting that prolactin is the hormone of the emotion we associate with love, which most cultures associate with the heart. Prolactin is made in men as well as women and children, for all of our lives, and has functions other than the primary one of lactation. It is intimately connected with melatonin and hence ajna chakra, with TRH and hence with vishuddhi chakra, with glucocorticoids and our stress levels and with oestrogen and hence female sexuality. As the hormone of love this makes perfect sense.

The solar plexus: manipura chakra

Satyananda says that manipura chakra is located behind the navel and causes old age, decay and emaciation by burning up the nectar of immortality. It is also connected with the sense of sight and the eyes and it is the organ of action and hence is also connected with walking, the legs and the feet. The solar plexus is the locus for our 'gut feelings' about people and situations, and is connected with digestion and assimilation. It has also been linked with ambition, will, self-assertion, vital energy, power struggles, anger and jealousy. Manipura is the uppermost of the 'earthly' or base chakras.

There are two possible endocrine organs in the gut which could be linked with manipura: the pancreas and the adrenals.

The adrenals

The adrenals are the endocrine glands I consider are most strongly related to manipura. Most people know these as the 'fight or flight' glands in that adrenaline is produced when we are in a stressful situation and we burn up our body energy in order to cope with a crisis; adrenaline is the hormone of action. We feel the fire in our belly.

The pineal is connected with the adrenals, and in particular with adrenaline and the corticosteroids in many ways. The adrenals comprise two parts: the cortex and the medulla. The cortex secretes glucocorticoids such as corticosterone, on a rhythmic light-dark cycle linked with hormones from the pituitary and the hypothalamus. The glucucorticoids are involved with sugar metabolism and as stress protectors. The cortex also secrets mineralocorticoids which are involved in mineral balance, and also anxiety. The third sort of hormones produced by the cortex are the androgenic steroids which include testosterone, are involved in body building and anger; there is a steroid surge in the morning to help wake up. These are the stress-related hormones.

The adrenal medulla secretes adrenaline. The pineal inhibits release of all of these hormones, thus controlling our physical level of immediate short-term stress – as it does with the thyroids on a long-term basis. Melatonin is actually found in the gut as are the beta-carbolines. Beta-carbolines interact with adrenaline and noradrenaline uptake and outputs as well as with corticosterone secretion, thus interacting closely with the adrenal functions. Constant administration of small doses of beta-carbolines causes the weight of the adrenals to increase, whilst removal of the pineal gland causes enlarged adrenals. The significance of this enlargement of adrenals, as with the thyroids, when for some reason or other there is no pineal, is that the inhibitory effect on these glands has been removed so that they work overtime. And, as a result, one burns up. This can be understood in the spiritual as well as in the physical sense.

The pancreas

Some systems consider that the pancreas, which is involved in digestion and the input of energy and energy maintenance (the Islets of Langerhans within the pancreas make insulin, a glucose using hormone, and glucagon, a glucose saving hormone), is the endocrine organ of manipura chakra. This would make very good sense in terms of our Western concept of the solar plexus, and is certainly to be considered. Davidson (1989) mentions insulin and glucagon in this connection as the food factory of the body, that which gives us our physical energy.

However, there is a connection with the adrenals because the pancreas is turned off by adrenaline and noradrenaline, and adrenaline regulates the uptake of glucose. Therefore the pineal is connected with the pancreas via the adrenals.

— (The final part of this article will appear in the next issue.)