Opening of K(ATP) channels is mandatory for acquisition of ischemic tolerance by adenosine

A Reshef1, O Sperling, E Zoref-Shani

  • 1Department of Clinical Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Israel.

Neuroreport
|March 16, 2000
PubMed

Insights

Activating the adenosine mechanism in neurons confers ischemic tolerance by opening K(ATP) channels. This channel opening is essential for the entire duration of the protective effect, creating a wide time window of tolerance.

Area of Science:

  • Neuroscience
  • Cellular signaling
  • Ischemic tolerance

Background:

  • Adenosine receptors activate a signaling pathway (adenosine mechanism) inducing temporary ischemic tolerance.
  • Previous studies showed this mechanism, activated by adenosine receptors or protein kinase C (PKC), confers up to 72h ischemic tolerance.
  • The immediate phase of this tolerance depends on K(ATP) channel opening (glibenclamide sensitive).

Purpose of the Study:

  • To investigate the role of K(ATP) channels in the entire duration of adenosine-mediated ischemic tolerance.
  • To determine if K(ATP) channel opening is a mandatory step for sustained ischemic tolerance.

Main Methods:

  • Primary rat neuronal cultures were used.
  • Adenosine receptors and protein kinase C (PKC) were activated to induce the adenosine mechanism.
  • The effect of glibenclamide (a K(ATP) channel blocker) on ischemic tolerance duration was assessed.

Main Results:

  • The entire duration of ischemic tolerance induced by the adenosine mechanism was found to depend on K(ATP) channel opening.
  • Blocking K(ATP) channels abolished the sustained ischemic tolerance conferred by adenosine receptor activation.

Conclusions:

  • K(ATP) channel opening is a mandatory step in the adenosine mechanism.
  • Opening of K(ATP) channels is crucial for establishing the wide time window of ischemic tolerance.
  • The adenosine mechanism's protective effect against ischemia is critically dependent on sustained K(ATP) channel activity.

Related Concept Videos

G-Protein Gated Ion Channels01:21

G-Protein Gated Ion Channels

GPCRs are primarily responsible for our sense of smell, taste, and vision.  The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Ligand-Gated Ion Channel Receptor: Gating Mechanism01:30

Ligand-Gated Ion Channel Receptor: Gating Mechanism

Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
Primary Active Transport01:47

Primary Active Transport

In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps that are embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they...
Primary Active Transport01:29

Primary Active Transport

In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would not...
Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers01:12

Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers

Class III antiarrhythmic drugs are a group of medications that can prolong action potentials in the heart. They achieve this by blocking potassium channels or enhancing inward currents from sodium channels. However, these drugs have a unique property of "reverse use-dependence," which is most pronounced at slower heart rates and can lead to torsades de pointes—a specific type of arrhythmia. However, it is essential to note that excessive QT interval prolongation—a measure of the heart's...
Active Transport01:14

Active Transport

Active transport is a critical biological process that allows cells to move solutes against an electrochemical gradient. This process requires direct energy input and is characterized by its selectivity, saturability, and susceptibility to competitive inhibition.
Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...