A1-adenosine acute withdrawal response and cholecystokinin-8 induced contractures are regulated by Ca(2+)- and ATP-activated K(+) channels.

Abstract

In isolated guinea-pig ileum (GPI), the A1-adenosine acute withdrawal response is under the control of several neuronal signalling systems, including the μ/κ-opioid and the cannabinoid CB1 systems. It is now well established that after the stimulation of the A1-adenosine system, the indirect activation of both μ/κ-opioid and CB1 systems is prevented by the peptide cholecystokinin-8 (CCk-8). In the present study, we have investigated the involvement of the Ca(2+)/ATP-activated K(+) channels in the regulation of both acute A1-withdrawal and CCk-8-induced contractures in the GPI preparation. Interestingly, we found that: (a) the A1-withdrawal contracture is inhibited by voltage dependent Ca(2+)-activated K(+) channels, Kv, while it is enhanced by the voltage independent Ca(2+)-activated K(+) channels, SKCa; (b) in the presence of CCk-8, the inhibitory effect of the A1 agonist, CPA, on the peptide induced contracture is significantly enhanced by the voltage independent Ca(2+)-activated K(+) channel, SKCa; and (c) the A1-withdrawal contracture precipitated in the presence of CCk-8 is controlled by the ATP-sensitive potassium channels, KATP. Our data suggest, for the first time, that both Ca(2+)- and ATP-activated K(+) channels are involved in the regulation of both A1-withdrawal precipitated and CCk-8 induced contractures.

• Authors: Maria Grazia Cascio, Daniela Valeri, Steven J Tucker, Pietro Marini
• Journal: Pharmacological research (Pharmacol Res) 2015 May-Jun Vol. 95-96 Pg. 82-91 ISSN: 1096-1186 [Electronic] Netherlands
• PMID: 25836919 (Publication Type: Journal Article)
• Copyright: Copyright © 2015 Elsevier Ltd. All rights reserved.

Chemical References

• Adenosine A1 Receptor Agonists
• Adenosine A1 Receptor Antagonists
• KATP Channels
• Narcotic Antagonists
• Peptide Fragments
• Potassium Channel Blockers
• Potassium Channels, Calcium-Activated
• Receptor, Adenosine A1
• Receptors, Opioid
• cholecystokinin 8
• Cholecystokinin

Topics

• Adenosine A1 Receptor Agonists (pharmacology)
• Adenosine A1 Receptor Antagonists (pharmacology)
• Animals
• Cholecystokinin (pharmacology)
• Guinea Pigs
• Ileum (drug effects, metabolism, physiopathology)
• In Vitro Techniques
• KATP Channels (metabolism)
• Male
• Muscle Contraction (drug effects)
• Narcotic Antagonists (pharmacology)
• Peptide Fragments (pharmacology)
• Potassium Channel Blockers (pharmacology)
• Potassium Channels, Calcium-Activated (metabolism)
• Receptor, Adenosine A1 (metabolism)
• Receptors, Opioid (metabolism)
• Substance Withdrawal Syndrome (drug therapy, metabolism, physiopathology)