The Contribution of cocoa additive to cigarette smoking addiction

Page 52 of 207 RIVM report 650270002
Serotonin
concentrations up to 1.76 mg/l, but constriction at 17.6 mg/l (20).
see also heart rate
heart rate:
Serotonin does not appear to regulate blood pressure in the normal animal.
However, when platelets become activated in certain disease states, serotonin may
increase blood pressure. Serotonin exerts complex effects in the cardiovascular
system, including hypotension or hypertension, vasodilatation or vasoconstriction,
and/or bradycardia or tachycardia; the eventual response depends primarily on the
nature of the serotonin receptors involved. Serotonin produces positive inotropic
and chronotropic effects on the heart that are mediated by 5-HT1 receptors. These
effects may be blunted by stimulation of 5-HT3 receptors on afferent nerves of
baroreceptors and chemoreceptors. 5-HT3 receptors are also present on vagal
nerve endings in the coronary chemoreflex, characterized by inhibition of
sympathetic outflow and increased activity of the cardiac (efferent) vagus, leading
to profound bradycardia and hypotension (6, 21).
Renal system
diuresis: An intrarenal infusion of serotonin at a dose of 5 µg/min in anesthetized
dogs resulted in a biphasic response of renal blood flow which decreased
transiently then increased above the control level during prolonged infusion. The
prolonged infusion of serotonin also increased urine flow and urinary excretion of
Na + . Serotonin may exert its antidiuretic action via a 5-HT1-like receptor in the
tubules but the renal hemodynamic changes induced by serotonin may overcome
its antidiuretic action and evokes subsequently diuresis (22).
saluresis: After direct application of serotonin to the central nervous system
(CNS), increases in urinary excretion of Na+ and in the Na + /K + ratio were
observed, concomitant with depressor effects. Therefore, central serotoninergic
mechanisms are involved in the control of Na+ excretion in the hydrated rat (23).
Nervous system
central nervous system:
Serotonin exerts numerous effects on the CNS through the large family of
serotonin receptors. Serotonin plays a role in depression, agression, long term
memory, mental fatigue during endurance exercise (24-27). Serotonin is
furthermore involved in regulation of sleep, circadian rhythms, food intake (fat
and energy intake) and regulation of the BBB (brain blood barrier) function (13,
28, 29). The serotoninergic system is also involved in the nicotine dependency
(30, 31).
autonomic system: Serotonin can stimulate or inhibit nerves, depending on the site
and the type of receptor involved. Activation of 5-HT1 receptors on adrenergic
nerve terminals inhibits the release of the norepinephrine elicited by stimulation of
the sympathetic nervous system. 5-HT3 receptors located on various sensory
neurons mediate a depolarizing response, which may account for the ability of
serotonin to cause pain and itching, as well as respiratory stimulation and
cardiovascular reflex (6). Serotonin released from intestinal enterochromaffin cells
may act either directly on vagal afferents and/or pass to the circulation and