What is the mechanism of action of adenosine in the heart?
It acts on receptors in the cardiac AV node, significantly slowing 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.
Why does adenosine decrease heart rate?
Adenosine re- leased from working myocardium acts to increase oxygen supply by causing coronary vasodilation, and to decrease oxygen consumption by slowing heart rate and attenuating the excitatory effects of P-adrenergic stimulation (Fig. 1). Thus, adenosine acts as a nega- tive feedback modulator of cardiac work.
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] .
Why does adenosine increase blood flow?
The adenosine crosses the interstitial space to act on adenosine receptors on coronary arteriolar smooth muscle to cause vasodilation. The ensuing increase in coronary blood flow delivers more oxygen to the myocardium and thus returns myocardial Po2 back toward the normal operating range.
Does adenosine increase or decrease heart rate?
Adenosine has a key role in the adaptive response in pulmonary hypertension and heart failure, with the most relevant effects being slowing of heart rhythm, coronary vasodilation and decreasing blood pressure.
What are the side effects of adenosine?
Side effects of adenosine include:
- facial flushing.
- difficulty breathing.
- chest pain.
- heart attack.
- lightheadedness.
- dizziness.
- tingling in arms.
- numbness.
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?
Our data indicate that adenosine-induced vasoconstriction is initiated by activation of A1AR coupled to a PTX-sensitive Gi protein but that crosstalk between activated Gi and PLC, rather than inhibition of adenylate cyclase, is responsible for activation of the contractile apparatus.
How does adenosine affect the lungs?
Adenosine is produced in the inflamed and damaged lung where it plays numerous roles in the regulation of inflammation and tissue remodeling. Extracellular adenosine serves as an autocrine and paracrine signaling molecule by engaging cell surface adenosine receptors.
What are the side effects of dobutamine?
Common side effects of dobutamine include:
- increased heart rate and increased blood pressure,
- ventricular ectopic activity,
- nervousness,
- headache,
- nausea,
- vomiting,
- palpitations,
- low platelet counts (thrombocytopenia), or.
Does adenosine damage the heart?
Adenosine is released during hypoxia, ischemia, beta-adrenergic stimulation or inflammation and impacts heart rhythm and produces strong vasodilation in the systemic, coronary or pulmonary vascular system.
How 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.
Does adenosine actually stop the heart?
Does adenosine stop the heart? Yes, sometimes, when used as an IV push med for P.A.T. The stoppage is due to a brief delay in the return of S.A. activity to sinus rhythm.
What does adenosine do to the heart?
severe shortness of breath;
When not to use adenosine?
Adenosine should never be used in wide irregular tachycardias. Providers who are going to use adenosine must be experts in cardiac rhythm interpretation. They also must carefully review a rhythm
Does adenosine lower blood pressure?
It is known that adenosine decreases blood pressure (BP) level as well as blood pressure variability (BPV). However, there is little information about the effect of adenosine on BPV. With a computerized analytic system for BP and heart rate (HR) that could sample the data continuously in conscious, freely moving rats, we studied the effects of different agonists and antagonists of adenosine receptors on BPV in sinoaortic denervated (SAD) rats.
