A comparison of adenosine-induced cardioprotection and ischemic preconditioning in dogs. Efficacy, time course, and role of KATP channels.

Abstract

Background Adenosine has been proposed to be an important mediator of ischemic preconditioning. Intracoronary administration of adenosine has recently been shown to mimic the effects of preconditioning in isolated rabbit hearts. However, it is not known whether this agent can duplicate the effects of preconditioning in vivo or in other species. Thus, the first objective of the present study was to determine whether adenosine can limit myocardial necrosis to the same extent as preconditioning in anesthetized dogs. A second objective was to determine whether the duration of the adenosine-induced cardioprotection persisted as long as that of ischemic preconditioning. Finally, a third aim was to determine whether adenosine mediates its cardioprotection via the KAT channel,

KATP Channel Openers Facilitate Glutamate Uptake by GluTs in Rat Primary Cultured Astrocytes

“…Activation of post-synaptic K ATP channels causes membrane hyperpolarization, which limits neuronal excess excitation; activation of presynaptic K ATP channels can directly modulate neurotransmitter release from nerve terminals. Therefore, K ATP channel openers (KCOs) serve as efficient tools that can adjust cell excitability, and exhibit beneficial effects under pathological conditions such as ischemia, stroke, and neurodegenerative diseases (Yao and Gross, 1994;Sargent et al, 1993;Liss et al, 2005). Emerging evidence including from our laboratory has revealed that the opening of K ATP channels play dominant protective roles in various models of neurodegenerative diseases such as Parkinson's disease (PD) (Tai et al, 2003;Wang et al, 2006;Yang et al, 2004).…”

Direct preconditioning of cultured chick ventricular myocytes. Novel functions of cardiac adenosine A2a and A3 receptors.

“…Preconditioning has been demonstrated in isolated perfused hearts of a number of mammalian species including dog, guinea pig, pig, rabbit, and rat (1)(2)(3)(4)(5)(6)(10)(11)(12)(13). Indirect evidence for such protective preconditioning also exists in humans (5,6,14).…”

Medical and Cellular Implications of Stunning, Hibernation, and Preconditioning

“…Activation of a variety of receptors (adenosine, acetylcholine, bradykinin, and others) that can mimic the cardioprotective effects of ischemic preconditioning may involve the K ATP channel, because glibenclamide and 5-HD were shown to block the cardioprotective effects of these agents. 213,214 However, not all studies have implicated K ATP channels in preconditioning. Some studies in rabbit hearts, isolated rabbit cardiomyocytes, and rats have not confirmed the importance of K ATP channels in preconditioning.…”