Possible Interaction: Niacin and Serotonin

“ Niacin increases plasma PGD2 and serotonin in a rat model of flush.”

“ 5-HT release is modulated by a variety of neuromodulators acting on adrenoreceptors, nicotinic and muscarinic cholinoreceptors and 5-HT3 receptors (Racke et al. 1996).”

“It is suggested that niacin perhaps facilitates the release of free serotonin and promotes its action at the receptor sites.”

“Exogenous ligands such as galanthamine and the neurotransmitter 5-hydroxytryptamine , when applied in submicromolar concentrations with nicotinic agonists, significantly increase the frequency of opening of nicotinic receptor channels and potentiate agonist-activated currents.”

“S-zacopride, like renzapride and 5-HT , presynaptically inhibited nicotinic fast excitatory postsynaptic potentials, an effect that can be mediated by 5-HT1P or 5-HT1A receptors.”

“It is, therefore, suggested that diphasic effect of 5-HT on the nicotinic transmission is due mainly to a modulation of the ACh-release from presynaptic nerve terminals.”

“Thus serotonin , probably acting on 5-HT1A receptors, blocks effectively but indiscriminately all cholinergic facilitations, whether mediated by nicotinic or muscarinic receptors.”

“ Fast nicotinic excitatory postsynaptic potentials (EPSPs) and slow EPSPs recorded from S neurons in the myenteric plexus were suppressed by 5-HT , 5-CT, and DPAT; slow EPSPs in myenteric AH neurons were also inhibited by these agonists.”

“The evoked nicotinic excitatory postsynaptic potential and the adrenergic inhibitory postsynaptic potential were decreased by 5-hydroxytryptamine ; a portion of this inhibition showed desensitization and was blocked by ICS 205-930 as well as by the muscarinic receptor antagonists, atropine and pirenzepine.”

“ Nicotinic acid , an agent which may decrease cyclic AMP levels, decreased relaxation by serotonin.”