https://sci-hub.hkvisa.net/10.1016/j.mehy.2015.11.018
The pineal gland is located on the postero-dorsal aspect of third
ventricle and a portion of this organ is in direct contact with the
CSF due to an incomplete ependymal lining in the pineal recess
[46], an extension of the third ventricle. In the recess, a consistent
and relatively large area lacks an ependymal lining (allowing
pinealocytes to be directly bathed by the CSF [46,47] (Fig. 1). This
area documents the close physical association of the pinealocytes
and ventricular CSF. Thus, the substances synthesized by pineal
gland, including melatonin or some peptides, could readily be
released into the third ventricle. This relationship of the pineal
gland to the CSF presumably accounts for the much higher levels
of melatonin in CSF of third ventricle than those in circulation
[39,43]. The melatonin levels in third ventricle exhibit a concentration
gradient with CSF highest levels in the pineal recess [40,48].
This provides evidence that support the idea that the major route
of melatonin secretion is into the CSF of the third ventricle rather
than into the blood circulation [38–41].
So I blogged before - and the mainstream view - is the pineal gland is like the adrenal gland - it is activated by the sympathetic nervous system. As I pointed out this originates as a biophoton signal and then an electrical signal and then it turns into hormone production.
choroidal
artery [53] (Fig. 5). It has been reported that using rat as the
experimental animal, the minimum rate of pineal blood flow per
gram tissue exceeds that of most endocrine organs and is surpassed
only by that of the kidney [54]. It was calculated that the
pineal blood flow exceeds 0.0085% of the total cardiac output of
a rat or 8%/gram tissue for a 200 gram rat. Thus, the rate of pineal
blood flow is 16 times higher than that of the average blood flow
per gram tissue in rats. Such a high rate of blood perfusion to the
pineal gland is likely not simply explained by its high metabolic
activity. Based on its glomerular-like vascular structure, there is
reason to believe that pineal gland may also have a filtrating function
which is similar to the kidney suggesting that the gland may
participate in the CSF production.
This is fascinating to be sure.
so it filters the blood and cranks out cerebrospinal fluid on the other end!!
Wild.
CSF generation by pineal gland results in a robust melatonin circadian
rhythm in the third ventricle as an unique light/dark signal
My article series now featured!
thanks
Corpus Callosum primary role is inhibition
Fascinating.
In the pineal, the plasma filtered from the fenestrated capillaries
would enter the pericapillary space, which could then enter
canaliculi and eventually be directly released into the third ventricle
to form the CSF (Fig. 4). If only 5% of the blood supply to the
pineal gland would be filtered to form CSF, the pineal gland would
generate an estimated 45 ml CSF/day in an adult human. The brain
produces roughly 500 ml CSF/day and, thus, the pineal gland may
contribute up to 10% of the total CSF.
The choroid plexus are major sites of CSF secretion. The choroid
plexus and pineal gland have similar fenestrated capillaries which
are twisted and anastomosing to form a capillary network [49].
This network expands the luminal surface of the blood vessels of
both organs.
So meditation increases the brain pressure and therefore the blood flow rate through the pineal gland and thus an increase in cerebrospinal fluid production!
Collectively
the findings suggest that both choroid plexus and pineal
gland are sites of CSF production.
If the pineal gland does in fact produce CSF, what is the significance
of its CSF formation of this gland? This question remains
unanswered. In addition to the possibility that the pineal produces
CSF, the absorption of CSF by the pineal has been proposed by Sun
et al [49]. The dual functions of pineal gland regarding its CSF
secretion and absorption may depend on the fenestrated capillaries,
the constriction of the collecting vein and the hydrostatic pressure
of the glomerular-like structure. Potentially, during systole
when the collecting veins are constricted, CSF secretion is dominant
while during diastole with the relaxed venous constriction
the CSF absorption would be dominant.
Food including vegetables, fruits, cereals and meats contain significant amounts of melatonin [57–59] which, after absorption into the blood, could impact the bio-clock.So if that is true for melatonin - it is ALSO true for serotonin in the blood! This is the first admission I've seen of this since otherwise it is assumed the neurohormones can not bypass the blood barrier.
The pineal gland receives adrenergic innervation, which activates a cascade of circadian events that leads to the nightly formation of melatonin from serotonin. Serotonin is present at high levels in the pineal gland during the day and increases further at night in the absence of melatonin formation
Circadian levels of serotonin in plasma and brain after oral administration of tryptophan in rats
Serotonin, one of the most important neurotransmitters in the central nervous system, is synthesized by the amino acid, tryptophan. Given that this essential amino acid is consumed in the diet, the aim of this study was to evaluate the effect of orally administered L-tryptophan (125 mg/kg) on circadian variations in the levels of serotonin in brain and plasma. We used male Wistar rats of 14 +/- 2 weeks of age (n = 240), maintained under conditions of a 12-hr light:dark cycle, and food and water ad libitum. Tryptophan administration was by gavage in a daily single dose at 7 p.m. for 7 days. The serotonin levels were measured by ELISA every hour at night (8 p.m. to 8 a.m.) and every 4 hr during daytime (8 a.m. to 8 p.m.). The results show that in both the tryptophan-treated and untreated groups the highest values appeared during the beginning of the darkness with a peak at 9, 10 and 11 p.m. in controls, and at 9 p.m. in the tryptophan-treated group. After tryptophan administration, the levels of serotonin were significantly higher in the plasma and all the brain regions analysed than in the control group. This increase of serotonin levels was greater in the pineal gland than in other brain regions, and the least in plasma. In conclusion, oral administration of tryptophan during 7 days enhances serotonin levels over a 24-hr period, and produces an advance in the peak of serotonin in both plasma and different brain regions.
Tryptophan-enriched cereal intake improves nocturnal sleep, melatonin, serotonin, and total antioxidant capacity levels and mood in elderly humans
R Bravo, S Matito, J Cubero, SD Paredes, L Franco… - Age, 2013 - Springer
Melatonin and serotonin rhythms, which exhibit a close association with the endogenous circadian component of sleep, are attenuated with increasing age. This decrease seems to
Neuromodulation of the Pineal Gland via Electrical Stimulation of Its Sympathetic Innervation Pathway
Stimulation of the pineal gland via its sympathetic innervation pathway results in the production of N-acetylserotonin and melatonin.
exactly how different types of electrical response regulate this process is unknown. One possible mechanism could be pinealocytes engaging in self-regulation through glutamate release following hyperpolarisation of the cell membrane.
This explains why glutamate from MSG causes such wild dreams!
These experiments show that sympathetic innervation of the pineal gland is not simply a case of recruiting excitation of all pinealocytes to the same degree, and that some pinealocytes serve different roles upon receiving sympathetic innervation. Whilst an excitatory response may facilitate synthesis of melatonin, an inhibitory response may prevent this. This could be mediated via astrocytes in close proximity to the pinealocytes releasing glutamate (Villela et al., 2013) or GABA (Minchin and Iversen, 1974), or even neighbouring pinealocytes releasing GABA, as both neurotransmitters are known to decrease melatonin synthesis (Rosenstein et al., 1989).
https://mdpi-res.com/d_attachment/ijms/ijms-21-08806/article_deploy/ijms-21-08806.pdf
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