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Adenosine Pharmacological Effects

Adenosine Pharmacological Effects

In the heart and blood vessels, adenosine has profound effects. It helps to dilate or expand the blood vessels that supply the heart (coronary blood vessels) and thereby enhances blood supply to the heart muscles. Blood vessels all over the body also dilate when adenosine is administered.Apr 18, 2019

What is the role of adenosine?

In the body, adenosine helps in cellular energy transfer by forming molecules like adenosine triphosphate (ATP) and adenosine diphosphate (ADP). Adenosine also plays a role in signalling various pathways and functions in the body by forming signally molecules like cyclic adenosine monophosphate (cAMP).

Is adenosine a vasodilator or vasoconstrictor?

Adenosine is an ATP breakdown product that in most vessels causes vasodilatation and that contributes to the metabolic control of organ perfusion, i.e., to the match between oxygen demand and oxygen delivery.

What effect does adenosine have on how we feel?

Adenosine is a central nervous system neuromodulator that has specific receptors. When adenosine binds to its receptors, neural activity slows down, and you feel sleepy. Adenosine thus facilitates sleep and dilates the blood vessels, probably to ensure good oxygenation during sleep.

What is adenosine and what kinds of effects does it have on the human body?

Adenosine blocks electrical signals in the heart that cause irregular heart rhythms. ATP might also prevent changes in energy metabolism that cause weight loss in people with advanced cancer.

Why does adenosine cause vasodilation?

Since calcium regulates smooth muscle contraction, reduced intracellular calcium causes relaxation. In some types of blood vessels, there is evidence that adenosine produces vasodilation through increases in cGMP, which leads to inhibition of calcium entry into the cells as well as opening of potassium channels.

How does adenosine cause bronchoconstriction?

Adenosine produces bronchoconstriction in airways by directly acting on ARs in bronchial smooth muscle cells or indirectly by inducing the release of preformed and newly formed mediators from mast cells, and by acting on ARs on airway afferent sensory nerve endings (Hua et al.

How does adenosine cause vasoconstriction?

Although the dominant effect of adenosine in most vascular beds is vasodilation, the nucleoside can cause vasoconstriction in renal resistance vessels through activation of A1 adenosine receptors (A1AR).

How does adenosine affect dopamine?

Naturally rewarding stimuli (i.e. food, sex, etc) increase the activity of dopamine cells in the mesocorticolimbic dopamine system causing increased dopamine release in brain areas such as the nucleus accumbens.

Is adenosine excitatory or inhibitory?

1 In addition to its cardiovascular actions, adenosine is generally considered an inhibitory neuromodulator. It produces hyperpolarization of neu- rons, decreases nerve firing, and has central depressor actions.

What happens if you have too much adenosine?

In contrast, chronic overproduction of adenosine occurs in important pathological states, where long?lasting increases in the nucleoside levels are responsible for the bad side of adenosine associated with chronic inflammation, fibrosis and organ damage.

What happens to adenosine when you sleep?

3 With higher and higher concentrations, adenosine inhibits arousal and causes sleepiness. Then, adenosine levels decrease during sleep. Therefore, scientists have long extrapolated that high levels of adenosine in effect cause sleep.

What is adenosine triphosphate used for?

Adenosine 5′-triphosphate, or ATP, is the principal molecule for storing and transferring energy in cells. It is often referred to as the energy currency of the cell and can be compared to storing money in a bank.

Is adenosine a vasodilator in the kidney?

Adenosine (ADO) is a potent vasodilator in most tissues . In the kidney it can induce either vasoconstriction or vasodilation, depending on the prevailing stimulation of A1 or A2 receptors (A1R, A2R) [1, 2] .

Does epinephrine cause vasodilation?

Epinephrine binds both ? and ? adrenergic receptors to cause vasoconstriction and vasodilation. When activated, the ?1 receptor triggers smooth muscle contraction in blood vessels in the skin, gastrointestinal tract, kidney, and brain, among other areas.

Does adenosine cause coronary vasodilation?

Adenosine is a potent coronary vasodilator that interacts with a specific receptor on the coronary myocyte to result in relaxation of the vascular smooth muscle.

Does epinephrine cause bronchoconstriction?

Epinephrine clearly counteracted allergen-induced bronchoconstriction (Fig. 4). During placebo infu- sions the bronchial challenge tests induced broncho- constriction (according to the aforementioned criteria) in all patients at doses of 10 to 10,000 BE, the cal- culated median dose being -1040 BE.

Why is adenosine contraindicated in asthma?

Since airways inflammation and bronchial hyperreactivity are features of asthma, it is possible that intravenous adenosine may be associated with an increased intensity of dyspnea, and may cause bronchospasm, as noted anecdotally in previous reports.

Why does adenosine cause bronchospasm?

It has been suggested that this action of adenosine is due to its binding to specific purino receptors in the mast cells in the lungs and consequent release of mediators which elicit bronchoconstriction and asthma.

Why does nitric oxide cause vasodilation?

Nitric oxide is a compound produced by many cells of the body. It relaxes vascular smooth muscle by binding to the heme moiety of cytosolic guanylate cyclase, activating guanylate cyclase and increasing intracellular levels of cyclic-guanosine 3′,5′-monophosphate, which then leads to vasodilation.

How does adenosine affect heart rate?

In the heart adenosine decreases heart rate and also decreases the speed with which impulses flow between the heart muscles to bring about a contraction. Adenosine acts in opposition to adrenaline and also possesses anti-platelet action that prevents platelets from aggregating.

What is adenosine in pharmacology?

Adenosine is a purine nucleoside base, most commonly recognized with the molecule adenosine triphosphate, or ATP, and is used thoroughly throughout the entire body in general metabolism.[1] Adenosine’s use as a pharmacological drug works through receptors called purinergic adenosine receptors found throughout the body.

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