Possible Interaction: Caffeine and Papaverine

“This suggests that these alkaloids do not act at the intracellular level, unlike papaverine which inhibits the contractile response to caffeine and noradrenaline.”

“3 Phentolamine and yohimbine did not block the Ca2+ refill pathway; prazosin and nifedipine inhibited the reuptake of Ca2+ by an internal store sensitive only to noradrenaline; papaverine inhibited the refilling of caffeine‐ and noradrenaline‐sensitive Ca2+‐stores.”

“In contrast, papaverine (0.1 mm) significantly inhibited the contractions evoked by NA or caffeine in Ca2+‐free medium.”

“In the presence of 10(‐2) M‐caffeine , which elicited both IK(Ca) and ICl(Ca), papaverine (10(‐3) M) failed to activate either current and 10(‐3) M‐papaverine reduced the caffeine‐induced IK(Ca) by 94%.”

“The effects of dilazep, papaverine and EHNA, but not of dipyridamole, were antagonized by caffeine.”

“At higher doses of ADO and PAP, caffeine antagonized their depressant effects whereas at the lower doses of ADO and PAP in combination with caffeine there was behavioral stimulation.”

“6 In the Ca2+‐free solution containing EGTA (2 mm), the contraction evoked by 5‐hydroxytryptamine (10 μm) or caffeine (10 mm) was dose‐dependently inhibited by papaverine (>1 μm).”

“ Caffeine contraction induced in Ca-free, depolarizing solution was also enhanced by treatment with papaverine during Ca-loading.”

“It was possible to overcome the inhibitory action of papaverine temporarily by caffeine.”