PLD pathway involved in carbachol-induced Cl− secretion: possible role of TNF-α

Abstract

In a previous study, it was found that exposure to tumor necrosis factor-α (TNF-α) potentiated the electrophysiological response to carbachol in a time-dependent and cycloheximide-sensitive manner. It was deduced that the potentiation could be due to protein kinase C activity because of increased 1,2-diacylglycerol. It was also observed that propranolol could decrease the electrophysiological response to carbachol (Oprins JC, Meijer HP, and Groot JA. Am J Physiol Cell Physiol 278: C463–C472, 2000). The aim of the present study was to investigate whether the phospholipase D (PLD) pathway plays a role in the carbachol response and the potentiating effect of TNF-α. The transphosphatidylation reaction in the presence of the primary alcohol 1-butanol [leading to stable phosphatidylbutanol (Pbut) formation] was used to measure activity of PLD. The phosphatidic acid (PA) levels were also measured. Muscarinic stimulation resulted in an increased formation of Pbut and PA. TNF-α decreased levels of PA.