Uptake of glucose analogs reflects the rate of contraction of cultured myocytes.

The present study demonstrates that: a) adenosine and R-N6-(2-phenylisopropyl)-adenosine (R-PIA, A1 and A3 adenosine receptor agonist) inhibited [3H]deoxyglucose uptake or [3H]3-O-methyl-D-glucose uptake; b) sugar uptake reflects the rate of contraction in cardiac cultures; c) [3H]deoxyglucose uptake or [3H]3-O-methyl-D-glucose uptake are useful quantitative probes for beating rate evaluation. A 25-40% decrease in [3H]deoxyglucose uptake (p < 0.01) was obtained following 13-21 min treatment with 100 microM adenosine together with 1 microM dipyridamole or with 10 microM R-PIA, which inhibited spontaneous contractions. Adenosine (10 microM) attenuated spontaneous beating rate and inhibited approximately 55% of the [3H]deoxyglucose uptake following 22 h treatment (p < 0.01). 1 microM R-PIA also attenuated beating rate following either a short (1 min) or long (24 h) application and decreased [3H]deoxyglucose uptake by 20-30% (p < 0.01) during 0.5-24 h of treatment. A 157 +/- 9% and 205 +/- 11% increase (p < 0.01) in [3H]deoxyglucose uptake was obtained at 27 and 37 degrees C, respectively, compared with the uptake at 17 degrees C, which completely inhibited spontaneous contractions. Similar results [33 +/- 6% (p < 0.01) and 21 +/- 8% (p < 0.05) inhibition in [3H]deoxyglucose uptake] were obtained following 2 and 22 h of carbamylcholine treatment, respectively. This treatment also reduced spontaneous contractions. [3H] 3-O-Methyl-D-glucose uptake also decreased by 31 +/- 12% (p < 0.05) as a result of the arrest of contractions by adenosine. Elevations of 90 +/- 13% and 34 +/- 11% (p < 0.01) in [3H]deoxyglucose uptake were obtained following treatment with isoprenaline after 2 and 22 h application, respectively. It is concluded that adenosine and R-PIA inhibited [3H]deoxyglucose uptake or [3H] 3-O-methyl-D-glucose uptake in rat heart culture and that there is a linkage between the rate of cardiac contractions in culture and sugar uptake.