Serotonin secretion inhibition

The unusual flavonoid derivative kuwanon G, 30, is reported to lower blood pressure in rabbits when administered intravenously at a dose of l.Omg/kg of body weight (743). (-h)-Catechin [(-h)-cyanidan-3)ff-ol], 31, is remarkably bioactive. Among its recently reported biological effects are the following antianaphylactic (517), anticoagulant (569), antihepatotoxic (963), platelet aggregation inhibition (118), and serotonin secretion inhibition (100) effects. 

In addition to their functions as presynaptic autoreceptors, 0C2AR can also modulate release of other neurotransmitters (Figure 3). In the CNS, 0C2A and 0C2C receptors inhibit dopamine release in basal ganglia (Bucheler et al. 2002) as well as serotonin secretion in mouse hippocampus and brain cortex (Scheibner et al. 2001a). In the enteric nervous system, the release of acetylcholine as determined by [3H] -choline overflow from tissue slices was selectively inhibited by (X2aAR (Scheibner et al. 2002). 

Drugs that block binding sites include selective serotonin reuptake inhibitors (SSRIs). In 1970, the Eli Lilly Company developed fluoxetine (Prozac). Their research began with nizoxetine, a selective norepinephrine reuptake inhibitor. Of the compounds that inhibited reuptake of serotonin, norepinephrine, and dopamine, fluoxetine was the most potent and selective inhibitor of serotonin reuptake. It was approved for use by the FDA in December, 1987, and used to reduce excessive serotonin secretion from carcinoid tumors. 

Ecstasy produces its effects by causing massive amounts of serotonin and dopamine to be released from neurons in the brain. In addition, Ecstasy inhibits the ability of neurons to reabsorb these neurotransmitters after they are secreted. This has the overall effect of dramatically increasing the stimulation of serotonin receptors on nearby neurons. Ecstasy affects numerous brain regions, as described in Table 3.1 ... 

Antidepressants that increase serotonin activity can also indirectly decrease dopamine activity by inhibiting the activity of dopamine-secreting nerve cells. This effect on dopamine nerve cells is generally not of sufficient magnitude to treat psychosis, but it may explain why patients taking these antidepressants on rare occasions experience akathisia and other extrapyramidal side effects. 

Sulfinpyrazone is used in medicine as a nonsteroid anti-inflammatory, fever-reducing analgesic however, it is believed, that it inhibits cyclooxygenase of thrombocytes. In addition, it is also possible that its action is also linked with the action on membrane of thrombocytes and reduced quantities of secreted adenosine diphosphate and serotonin, which facilitate thrombocyte aggregation. Unlike aspirin, it has no effect on those who do not have irregular aggregation systems. 

C. Carcinoid tumors arise from neuroendocrine cells of the gut and secrete serotonin and gastrointestinal hormones, which activate the gastrointestinal tract and result in diarrhea. Most of these tumors have receptors for somatostatin, which inhibit secretion when activated, resulting in reduced activity of the gut. Octreotide is a stable analogue of... 

Serotonin 2A antagonism may reverse dopamine 2 antagonism in the tuberoinfundibular pathway. There is an antagonistic and reciprocal relationship between serotonin and dopamine in the control of prolactin secretion from the pituitary lactoroph cells. That is, dopamine inhibits prolactin release by stimulating D2 receptors (Fig. 11—30), whereas serotonin promotes prolactin release by stimulating 5HT2A receptors (Fig. 11—31). 

Results of pharmacological studies employing antagonists to various neurotransmitters reveal that neurons that transmit signals with endogenous kappa and/or mu opioids, serotonin, histamine and acetylcholine are involved to some extent with stress-induced inhibition of TIDA neurons and the consequent secretion of prolactin (Demarest et al., 1985b,c Freeman et al., 2001). 

Serotonin (= 5- Ananas comosus (pineapple) Inhibits insulin secretion... 

Serotonin Usually inhibitory helps control mood, influences sleep, and inhibits pain pathways in the spinal cord. Secreted by subcortical structures into hypothalamus, brain, and spinal cord. There are many subtypes of serotonin receptors. Diffuse and widespread symptoms depression, headache, diarrhea, constipation, sexual dysfunction, and other medical symptoms. The selective serotonin reuptake inhibitors (SSRIs), the most commonly used antidepressants, work specifically on this neurotransmitter system. 

The source of the ergot strongly influences the type of alkaloids present, as well as the clinical picture of ergotism [171]. The ergot alkaloids have three types of physiological effects they cause contraction of smooth muscle, they block the action of serotonin and adrenaline, and they act on the hypothalamic-pituitary system to inhibit the secretion of prolactin. These properties have led to their being used to induce uterine contractions, to relieve migraine headaches, and to treat prolactin-dependent disorders. 

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