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Involvement of protein kinase A activation and phospholipase A(2) inhibition in the adenosine-activated basolateral 50 pS K(+) channels in the thick ascending limb of the rat kidney

SUI Hong-Yu, LUAN Hai-Yan, LIU Yu-Jie

Department of Physiology, Jiamusi University, Jiamusi 154002, China； Department of Pharmacology, Harbin Medical University, Harbin 150081, China

Abstract

The present study was designed to investigate the role of protein kinase A (PKA) and phospholipase A(2) (PLA(2)) in the stimulating effect of adenosine on the basolateral 50 pS K(+) channels in the thick ascending limb (TAL) of the rat kidney. Under the anatomic microscope, the TAL was dissected. The current of 50 pS K(+) channels were recorded by patch clamp technology. The protein expression of phosphorylated PKA and phosphorylated PLA(2) were examined by Western blot. The results showed that cyclohexyladenosine (CHA), an analog of adenosine, increased the 50 pS K(+) channel activity (P < 0.05). In the presence of H8, an antagonist of PKA, CHA did not affect the 50 pS K(+) channel activity. In the presence of AACOCF3 (an antagonist of PLA(2)), CHA did not further increase the 50 pS K(+) channel activity. CHA increased phosphorylation level of PKA, whereas inhibited phosphorylation of PLA(2) in the TAL of the rat kidney (P < 0.01). Furthermore, after blocking the PLA(2) with AACOCF3, CHA still increased the expression of phosphorylated PKA. On the contrary, CHA did not obviously change the expression of phosphorylated PLA(2) after H8 pretreatment. The results suggest that the stimulation of basolateral 50 pS K(+) channels by CHA is mediated by the activation of PKA followed by the inhibition of PLA(2) in the TAL of the rat kidney.

Key words: K+ channel; adenosine; protein kinase A; phospholipase A2; thick ascending limb

Received: 2011-12-27　　Accepted: 2012-03-20

Corresponding author: 隋洪玉　　E-mail: suihongyuhappy@163.com

Citing This Article：

SUI Hong-Yu, LUAN Hai-Yan, LIU Yu-Jie. Involvement of protein kinase A activation and phospholipase A(2) inhibition in the adenosine-activated basolateral 50 pS K(+) channels in the thick ascending limb of the rat kidney. Acta Physiol Sin 2012; 64 (4): 449-454 (in Chinese with English abstract).