Serotonin-mediated neurotransmission

A fourth modification of the classical model involves nitric oxide (NO), a new form of nonsynaptic interneuronal communication, or volume transmission. Nitric Oxide inhibits the uptake of dopamine, norepinephrine (Lonart and Johnson, 1994), and serotonin (Asano et ah, 1997) into neurons and is closely linked to glutamate-mediated neurotransmission. Nitric Oxide synthase is switched on only by glutamatergic receptors and appears to enhance the strength of glutamatergic input to monoaminergic neurons without requiring direct synaptic contact (Kiss and Vizi, 2001). 

Ciranna, L. 2006. Serotonin as a modulator of glutamate- and GABA-mediated neurotransmission implications in physiological function in pathology. Curr. Neuropharmacol. 4 101-114. 

Inhibition of monoamine oxidase has been proposed as a possible mechanism underlying the hydrogen sulfide-mediated disruption of neurotransmission in brain stem nuclei controlling respiration (Warenycia et al. 1989a). Administration of sodium hydrosulfide, an alkali salt of hydrogen sulfide, has been shown to increase brain catecholamine and serotonin levels in rats. It has also been suggested that persulfide formation resulting from sulfide interaction with tissue cystine and cystinyl peptides may underlie some... 

While much emphasis has been placed on alterations in noradrenergic neurotransmission, TCA drugs are not without effect on serotonin (5-HT) neurotransmission. Long-term studies with TCA drugs in animals have demonstrated postsynaptic supersensitivity to serotonin (5-HTia) receptor agonists at serotonin synapses, with an associated enhancement of serotonergic neurotransmission. The sensitization to 5-HTia agonists is mediated in part by an increase in the density of postsynaptic 5-HTia receptors. Enhancement of trans-... 

Alprazolam (Xanax /Pharmacia), a benzodiazepine derivative is used for the treatment of both anxiety and panic disorder and buspirone (Buspar /Bristol-Myers Squibb) is indicated for the treatment of anxiety disorders. The mechanism of action of buspirone is distinct from that of the benzodiazepines and is believed to be mediated mainly through modulation of serotonergic neurotransmission via its interaction with the 5-HT1A serotonin receptor subtype. 

Serotonin Agonists. Dysfunction of neurotransmission mediated by 5-hydroxy-tryptamine (5-HT serotonin) occurs in the basal ganglia of patients with PD, and excessive serotonergictransmission may contribute to dyskinesias associated with dopaminergic treatments (186). 5-HT receptors are expressed presynaptically on 5-HT terminals, where they limit serotonin release as autore-ceptors (187). Their activation should decrease 5-HT release and perhaps alleviate dopaminergic dyskinesias in PD (188). Because 5-HTia receptor stimulation can reverse par-... 

In the early 1970s, evidence of the role of serotonin (5-hydroxytryptamine or 5-HT) in depression began to emerge and the hypothesis that enhancing 5-HT neurotransmission would be a viable mechanism to mediate antidepressant response was put forward. In 1968, Arvid Carlsson (Goteborg, Sweden) had already found that, when an electrical impulse passed from one neuron to another, serotonin was released into the space between the neurons - the synapse - to help the message to be transmitted and its... 

Local application of 8-OH-DPAT in the raph4 nuclei reduces the firing rate of serotonergic neurons by acting on the somatodendritic autoreceptor. This in turn leads to a reduction of the serotonergic neurotransmission, i.e. less serotonin is released in the synaptic cleft. It is not known which of the postsynaptic receptors is critically involved in the mediation of LLR. As far as we know, no local application studies have been performed in the major projection areas of the serotonin system. 

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