How does adenosine affect the circulatory system?

How does adenosine affect the circulatory system?

Adenosine is known to regulate myocardial and coronary circulatory functions. Adenosine not only dilates coronary vessels, but attenuates beta-adrenergic receptor-mediated increases in myocardial contractility and depresses both sinoatrial and atrioventricular node activities.

What does adenosine do to blood vessels?

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.

How does adenosine slow AV conduction?

It acts on receptors in the cardiac AV node, significantly reducing conduction time. [3] This effect occurs by activation of specific potassium channels, driving potassium outside of cells, and inhibition of calcium influx, disrupting the resting potential of the slow nodal cardiac myocyte.

How does adenosine affect the heart?

In the heart adenosine acts on the sinus node that is responsible for firing new impulses that bring about contraction of the heart. From the sinus node the impulse passes via the atrioventricular (AV) node. Adenosine prevents firing of new impulses and also prevents conduction of the impulse via the AV node.

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.

Is adenosine a vasodilator or vasoconstrictor?

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] .

How does adenosine affect the AV node?

In terms of its electrical effects in the heart, adenosine decreases heart rate and reduces conduction velocity, especially at the AV node, which can produce atrioventricular block.

How does adenosine affect lungs?

Although physiological levels of extracellular adenosine might be important in the resolution of inflammation or tissue repair by activation of high-affinity adenosine receptors, elevated levels of adenosine may lead to the exacerbation of lung inflammation and damage through the activation of low-affinity adenosine …

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 adenosine cause vasodilation?

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. In cardiac tissue, adenosine binds to type 1 (A1) receptors, which are coupled to Gi-proteins.

What does adenosine do for SVT?

When SVT is not terminated by vagal maneuvers, short-term management involves intravenous adenosine or calcium channel blockers. Adenosine is a short-acting drug that blocks AV node conduction; it terminates 90% of tachycardias due to AVNRT or AVRT.

What are the adverse effects of adenosine?

Injections of adenosine can cause breathing problems and chest pain, especially when given at high doses. Adenosine can also cause headache, heart pounding, low blood pressure, nausea, sweating, flushing, lightheadedness, sleep problems, coughing, and anxiety.

What are the effects of adenosine on the heart?

Finally, adenosine by acting on presynaptic purinergic receptors located on sympathetic nerve terminals inhibits the release of norepinephrine. In terms of its electrical effects in the heart, adenosine decreases heart rate and reduces conduction velocity, especially at the AV node, which can produce atrioventricular block.

How does adenosine work in the sympathetic nervous system?

Adenosine has far-reaching effects as an extracellular signaling molecule inducing vasodilation in most vascular beds, regulating activity in the sympathetic nervous system, having antithrombotic properties, and reducing blood pressure and heart rate 1).

How does adenosine work on L type calcium channels?

Inhibition of L-type calcium channels also decreases conduction velocity (negative dromotropic effect) particularly at the atrioventricular (AV) nodes. Finally, adenosine by acting on presynaptic purinergic receptors located on sympathetic nerve terminals inhibits the release of norepinephrine.

How does adenosine work in the extracellular space?

On the other hand, adenosine in the extracellular space is formed by the action of enzyme ecto-5′ nucleotidase 9). Apart from a simple degradation product, adenosine produces multiple physiological effects such as regulation of blood flow, heart rate and heart contractility through activation of different adenosine receptors 10).