5-Hydroxytryptamine, Hypertension

Reserpine is a Rauwolfia alkaloid that has been used for centuries to treat insanity, insomnia and hypertension in humans. Reserpine inhibits normal sympathetic activity in both the CNS and the peripheral nervous system by binding to catecholamine storage vesicles, causing catecholamines to leak into the synapse so that they are not available for release when the presynaptic neuron is stimulated. This prevents the normal magnesium and ATP-dependent storage of catecholamines and 5-hydroxytryptamine in nerve cells, the result being catecholamine (norepinephrine (noradrenaline)) depletion. This results in the inhibition of normal sympathetic activity. 

Further evidence that central 5-hydroxytryptamine (5-HT) neurones are involved in cardiovascular control systems is found in the observation that a central administration of the selective neurotoxin 5 6-dihydroxy-tryptamine causes a significant delay in the development of hypertension in young spontaneously hypertensive rats (SHRs).30 a further demonstration of the centrally-mediated hypotensive effect of methysergide has appeared 31 this may not be a result of 5-HT antagonism. 

Blood pressure can be regulated by receptor, enzyme, endogerous substance, and cell, such as bradykinin B2-receptor, ACE, 5-Hydroxytryptamine, and endothelia cell. Based on these facts, the human plasma assay [131], pulmonary hypertension assay [132], coronary arteries (CA) constriction assay [133], MCAO and HSPG assay [134], and temperature assay in awake subjects [135] are established. 

Carbon and ceramic electrodes have been used for quantitative and qualitative recordings of the neurotransmitters dopamine (DA), 5-hydroxytryptamine (5-HT), and their metabolites 3,4-dihydroxyphenyl-acetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA), and L-glutamate. Nitric oxide can also be recorded. In this case the carbon surface of the electrode is covered with a p-type semiconducting polymeric porphyrin that acts as a catalyst for the oxidation of nitric oxide. Nitric oxide is responsible for the activity of the endothelium-derived relaxing factor associated with hypertension, diabetes, ischemia, and arteriosclerosis. 

Bufotenine ( = iV, -dimethyl-5-hydroxytryptamine) has a more regular and powerful hypertensive effect in dogs than 5-hydroxytryptamine. ... 

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