Possible Interaction: Adenosine and Methoxamine

“ Methoxamine (10 to 100 µM) produced up to a two-fold increase in tissue from adult animals only in the presence of optimal concentrations of adenosine (40 to 100 µM), but had no effect in neonatal tissue.”

“ Methoxamine and phenylephrine also reduced the extent of accumulation of cyclic adenosine-3′,5′-monophosphate , but only when they were present at relatively high concentrations (above 100 μmol·l-1).”

“Further application of either the α1‐adrenoceptor agonist methoxamine (100 μM) or the diacylglycerol analogue 1,2‐dioctanoyl‐sw‐glycerol (DOG, 100 μm) also increased the adenosine concentration by 35.1 ± 10.0% (n= 6, P < 0.05) or 40.6 ± 8.3% (n= 5, P < 0.05), respectively.”

“ Adenosine release during hypoxia and reperfusion was augmented in the methoxamine- and PMA-pretreated cardiomyocytes compared with the untreated cardiomyocytes, which was inhibited by alpha, beta-methyleneadenosine 5'-diphosphate (AOPCP), an inhibitor of ecto-5'-nucleotidase.”

“In the presence of methoxamine, adenosine induced a significant greater decrease in mean arterial pressure, and increase in cardiac index and vascular conductance.”

“ Methoxamine infusion induced an enhanced response to adenosine infusion.”

“The release of the adenine nucleotides and adenosine induced by methoxamine (10 microM), an alpha 1‐adrenoceptor agonist, was greater from artery segments from young rats than from old rats.”

“ Methoxamine also caused the release of adenosine and the adenine nucleotides which was reduced by 93% by removal of the endothelium.”

“The stimulatory interaction of methoxamine with alpha adrenergically regulated cyclic AMP-generating systems differs from the interaction of norepinephrine … the following observations: 1) the stimulatory effects of methoxamine and norepinephrine are nearly additive; 2) the stimulatory effects of methoxamine … adenosine are nearly additive, whereas the … much more than additive.”