Sucrose-stimulated subsecond transient increase in cGMP level in rat intact circumvallate taste bud cells.
Initial sweet taste transduction is expected to occur in the subsecond time range. We demonstrate a rapid and transient (75-250 ms) increase of cGMP (but not cAMP) level in rat intact circumvallate taste cells after stimulation by sucrose. This rapid increase does not occur in nonsensory epithelial cells. Pretreatment with a nonspecific phosphodiesterase (PDE) inhibitor (IBMX), a specific cAMP-PDE4 inhibitor (denbufylline), or an adenylyl cyclase activator (forskolin) all increased basal cAMP and abolished the sucrose-stimulated cGMP increase at 150 ms. Pretreatment with a soluble guanylyl cyclase inhibitor (1H-[1,2,4]oxadiazolo[4, 3-a]quinoxalin-1-one) reduced, whereas a specific cGMP-PDE inhibitor (zaprinast) abolished, the sucrose-stimulated cGMP increase. It is proposed that cGMP is involved in the initial stage of sugar taste transduction and that cGMP is more significant than cAMP at this stage. Activation of soluble guanylyl cyclase and inhibition of cGMP-PDE may be involved in the transient elevation of cGMP in response to sucrose stimulation. Moreover, it appears that cAMP level must remain low for sucrose to stimulate an increase in cGMP.
Krizhanovsky
V
V
Institute of Biochemistry, Food Science, and Nutrition, Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76-100, Israel.
Agamy
O
O
Naim
M
M
D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D000242:Cyclic AMP / Q000037:antagonists & inhibitors; D006152:Cyclic GMP / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013395:Sucrose / Q000494:pharmacology*; D013650:Taste Buds / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
D000067956:Adenylyl Cyclase Inhibitors; D004791:Enzyme Inhibitors; D010726:Phosphodiesterase Inhibitors; D013395:Sucrose; D000242:Cyclic AMP; D006162:Guanylate Cyclase; D006152:Cyclic GMP