Stimulation of A(₂a) adenosine receptor abolishes the inhibitory effect of arachidonic acid on the basolateral 50-pS K channel in the thick ascending limb.
نویسندگان
چکیده
The basolateral 50-pS K channels are stimulated by a cAMP-dependent pathway and inhibited by cytochrome P-450-omega-hydroxylase-dependent metabolism of arachidonic acid (AA) in the rat thick ascending limb (TAL). We now used the patch-clamp technique to examine whether stimulation of adenosine A(₂a) receptor modulates the inhibitory effect of AA on the basolateral 50-pS K channels in the medullary TAL. Stimulation of adenosine A(₂a) receptor with CGS-21680 or inhibition of phospholipase A₂ (PLA₂) with AACOCF3 increased the 50-pS K channel activity in the TAL. Western blot demonstrated that application of CGS-21680 decreased the phosphorylation of PLA(2) at serine residue 505, an indication of inhibiting PLA₂ activity. In the presence of CGS-21680, inhibition of PLA₂ had no further effect on the basolateral 50-pS K channels. The possibility that CGS-21680-induced stimulation of the basolateral 50-pS K channels was partially achieved by inhibition of PLA₂ in the TAL was also supported by the observation that CGS-21680 had no additional effect in the presence of AACOCF3. Moreover, stimulation of adenosine A(₂a) receptor with CGS-21680 also abolished the inhibitory effect of AA and 20-hydroxyeicosatetraenoic acid (20-HETE) on the 50-pS K channels. The effect of CGS-21680 on AA and 20-HETE-mediated inhibition of the 50-pS K channels was mediated by cAMP because application of membrane-permeable cAMP analog, dibutyryl-cAMP, not only increased the 50-pS K channel activity but also abolished the inhibitory effect of AA and 20-HETE. We conclude that stimulation of adenosine A(₂a) receptor increased the 50-pS K channel activity in the TAL, an effect that is achieved by suppression of PLA₂ activity and 20-HETE-induced inhibition.
منابع مشابه
Stimulation of A2a adenosine receptor abolishes the inhibitory effect of arachidonic acid on the basolateral 50-pS K channel in the thick ascending limb
Wang M, Sui H, Li W, Wang J, Liu Y, Gu L, Wang W-H, Gu R. Stimulation of A2a adenosine receptor abolishes the inhibitory effect of arachidonic acid on the basolateral 50-pS K channel in the thick ascending limb. Am J Physiol Renal Physiol 300: F906–F913, 2011. First published January 5, 2011; doi:10.1152/ajprenal.00617.2010.—The basolateral 50-pS K channels are stimulated by a cAMP-dependent pa...
متن کاملArachidonic acid inhibits K channels in basolateral membrane of the thick ascending limb.
We have used the patch-clamp technique to study the effect of arachidonic acid (AA) on the basolateral K channels in the medullary thick ascending limb (mTAL) of rat kidney. An inwardly rectifying 50-pS K channel was identified in cell-attached and inside-out patches in the basolateral membrane of the mTAL. The channel open probability (P(o)) was 0.51 at the spontaneous cell membrane potential ...
متن کاملAdenosine stimulates the basolateral 50 pS K channels in the thick ascending limb of the rat kidney.
We used the patch-clamp technique to examine the effect of adenosine on the basolateral K channels in the thick ascending limb (TAL) of the rat kidney. A 50-pS inwardly rectifying K channel was detected in the basolateral membrane, and the channel activity was decreased by hyperpolarization. Application of adenosine (10 microM) increased the activity of basolateral 50 pS K channels, defined by ...
متن کاملDietary K intake regulates the response of apical K channels to adenosine in the thick ascending limb.
We used the patch-clamp technique to study the effect of adenosine on the apical 70-pS K channel in the thick ascending limb (TAL) of the rat kidney. Application of 1 microM cyclohexyladenosine (CHA), an adenosine analog, stimulated apical 70-pS K channel activity and increased the product of channel open probability and channel number (NP(o)) from 0.34 to 0.7. Also, addition of CGS-21680, a sp...
متن کاملAngiotensin II stimulates basolateral 50-pS K channels in the thick ascending limb.
We used the patch-clamp technique to examine the effect of angiotensin II (ANG II) on the basolateral K channels in the thick ascending limb (TAL) of the rat kidney. Application of ANG II increased the channel activity and the current amplitude of the basolateral 50-pS K channel. The stimulatory effect of ANG II on the K channels was completely abolished by losartan, an inhibitor of type 1 angi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- American journal of physiology. Renal physiology
دوره 300 4 شماره
صفحات -
تاریخ انتشار 2011