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Effects of cannabinoids on caffeine contractures in slow and fast skeletal muscle fibers of the frog.

Huerta M, Ortiz-Mesina M, Trujillo X, Sánchez-Pastor E, Vásquez C, Castro E, Velasco R, Montoya-Pérez R, Onetti C - J. Membr. Biol. (2009)

Bottom Line: This ACPA effect was not statistically significant with respect to the reduction in tension in slow muscle fibers.Moreover, we detected the presence of mRNA for the cannabinoid CB(1) receptor on fast and slow skeletal muscle fibers, which was significantly higher in fast compared to slow muscle fiber expression.In conclusion, our results suggest that in the slow and fast muscle fibers of the frog cannabinoids diminish caffeine-evoked tension through a receptor-mediated mechanism.

View Article: PubMed Central - PubMed

Affiliation: Unidad de Investigación Dr. Enrico Stefani del, Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colonia Villa San Sebastián, Colima, México.

ABSTRACT
The effect of cannabinoids on caffeine contractures was investigated in slow and fast skeletal muscle fibers using isometric tension recording. In slow muscle fibers, WIN 55,212-2 (10 and 5 microM) caused a decrease in tension. These doses reduced maximum tension to 67.43 +/- 8.07% (P = 0.02, n = 5) and 79.4 +/- 14.11% (P = 0.007, n = 5) compared to control, respectively. Tension-time integral was reduced to 58.37 +/- 7.17% and 75.10 +/- 3.60% (P = 0.002, n = 5), respectively. Using the CB(1) cannabinoid receptor agonist ACPA (1 microM) reduced the maximum tension of caffeine contractures by 68.70 +/- 11.63% (P = 0.01, n = 5); tension-time integral was reduced by 66.82 +/- 6.89% (P = 0.02, n = 5) compared to controls. When the CB(1) receptor antagonist AM281 was coapplied with ACPA, it reversed the effect of ACPA on caffeine-evoked tension. In slow and fast muscle fibers incubated with the pertussis toxin, ACPA had no effect on tension evoked by caffeine. In fast muscle fibers, ACPA (1 microM) also decreased tension; the maximum tension was reduced by 56.48 +/- 3.4% (P = 0.001, n = 4), and tension-time integral was reduced by 57.81 +/- 2.6% (P = 0.006, n = 4). This ACPA effect was not statistically significant with respect to the reduction in tension in slow muscle fibers. Moreover, we detected the presence of mRNA for the cannabinoid CB(1) receptor on fast and slow skeletal muscle fibers, which was significantly higher in fast compared to slow muscle fiber expression. In conclusion, our results suggest that in the slow and fast muscle fibers of the frog cannabinoids diminish caffeine-evoked tension through a receptor-mediated mechanism.

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Effects of WIN 55,212-2 on caffeine contractures in slow muscle fibers. In a and b, tension decreased in the presence of WIN 55,212-2 (10 and 5 μM, respectively). Control caffeine contractures in normal solution are also shown (upper records). This effect of WIN 55,212-2 was reversible. Different muscle bundles were used for each experiment
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Fig3: Effects of WIN 55,212-2 on caffeine contractures in slow muscle fibers. In a and b, tension decreased in the presence of WIN 55,212-2 (10 and 5 μM, respectively). Control caffeine contractures in normal solution are also shown (upper records). This effect of WIN 55,212-2 was reversible. Different muscle bundles were used for each experiment

Mentions: It is known that cannabinoids can affect muscle activity (Baker et al. 2000, 2001; DiMarzo et al. 2000; Mackie 2006; Sañudo-Pena et al. 2000), but little information exists about the mechanism of action of cannabinoids on skeletal muscle. To determine whether cannabinoids directly modulate tension in slow skeletal muscle fibers, we used the cannabinoid agonist WIN 55,212-2. WIN was added to the external medium 5 min previous, to induce the caffeine contracture, and kept throughout the contracture. Addition of this agonist (10 μM) to the external medium decreased the tension evoked by 6 mm of caffeine; the maximum tension was clearly reduced to 67.43 ± 8.07% (P = 0.02, n = 5), while tension-time integral was reduced to 58.37 ± 7.17% (P = 0.0001, n = 5), compared to the control (Fig. 3a). Figure 3b shows caffeine contractures in normal solution before and after adding WIN 5 μM; the maximum tension was reduced to 79.4 ± 14.11% (P = 0.007, n = 5), while tension-time integral was reduced to 75.1 ± 3.6% (P = 0.002, n = 5). Thus, WIN at different concentrations reduces the tension of caffeine contractures in slow skeletal muscle fibers.Fig. 3


Effects of cannabinoids on caffeine contractures in slow and fast skeletal muscle fibers of the frog.

Huerta M, Ortiz-Mesina M, Trujillo X, Sánchez-Pastor E, Vásquez C, Castro E, Velasco R, Montoya-Pérez R, Onetti C - J. Membr. Biol. (2009)

Effects of WIN 55,212-2 on caffeine contractures in slow muscle fibers. In a and b, tension decreased in the presence of WIN 55,212-2 (10 and 5 μM, respectively). Control caffeine contractures in normal solution are also shown (upper records). This effect of WIN 55,212-2 was reversible. Different muscle bundles were used for each experiment
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2697372&req=5

Fig3: Effects of WIN 55,212-2 on caffeine contractures in slow muscle fibers. In a and b, tension decreased in the presence of WIN 55,212-2 (10 and 5 μM, respectively). Control caffeine contractures in normal solution are also shown (upper records). This effect of WIN 55,212-2 was reversible. Different muscle bundles were used for each experiment
Mentions: It is known that cannabinoids can affect muscle activity (Baker et al. 2000, 2001; DiMarzo et al. 2000; Mackie 2006; Sañudo-Pena et al. 2000), but little information exists about the mechanism of action of cannabinoids on skeletal muscle. To determine whether cannabinoids directly modulate tension in slow skeletal muscle fibers, we used the cannabinoid agonist WIN 55,212-2. WIN was added to the external medium 5 min previous, to induce the caffeine contracture, and kept throughout the contracture. Addition of this agonist (10 μM) to the external medium decreased the tension evoked by 6 mm of caffeine; the maximum tension was clearly reduced to 67.43 ± 8.07% (P = 0.02, n = 5), while tension-time integral was reduced to 58.37 ± 7.17% (P = 0.0001, n = 5), compared to the control (Fig. 3a). Figure 3b shows caffeine contractures in normal solution before and after adding WIN 5 μM; the maximum tension was reduced to 79.4 ± 14.11% (P = 0.007, n = 5), while tension-time integral was reduced to 75.1 ± 3.6% (P = 0.002, n = 5). Thus, WIN at different concentrations reduces the tension of caffeine contractures in slow skeletal muscle fibers.Fig. 3

Bottom Line: This ACPA effect was not statistically significant with respect to the reduction in tension in slow muscle fibers.Moreover, we detected the presence of mRNA for the cannabinoid CB(1) receptor on fast and slow skeletal muscle fibers, which was significantly higher in fast compared to slow muscle fiber expression.In conclusion, our results suggest that in the slow and fast muscle fibers of the frog cannabinoids diminish caffeine-evoked tension through a receptor-mediated mechanism.

View Article: PubMed Central - PubMed

Affiliation: Unidad de Investigación Dr. Enrico Stefani del, Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colonia Villa San Sebastián, Colima, México.

ABSTRACT
The effect of cannabinoids on caffeine contractures was investigated in slow and fast skeletal muscle fibers using isometric tension recording. In slow muscle fibers, WIN 55,212-2 (10 and 5 microM) caused a decrease in tension. These doses reduced maximum tension to 67.43 +/- 8.07% (P = 0.02, n = 5) and 79.4 +/- 14.11% (P = 0.007, n = 5) compared to control, respectively. Tension-time integral was reduced to 58.37 +/- 7.17% and 75.10 +/- 3.60% (P = 0.002, n = 5), respectively. Using the CB(1) cannabinoid receptor agonist ACPA (1 microM) reduced the maximum tension of caffeine contractures by 68.70 +/- 11.63% (P = 0.01, n = 5); tension-time integral was reduced by 66.82 +/- 6.89% (P = 0.02, n = 5) compared to controls. When the CB(1) receptor antagonist AM281 was coapplied with ACPA, it reversed the effect of ACPA on caffeine-evoked tension. In slow and fast muscle fibers incubated with the pertussis toxin, ACPA had no effect on tension evoked by caffeine. In fast muscle fibers, ACPA (1 microM) also decreased tension; the maximum tension was reduced by 56.48 +/- 3.4% (P = 0.001, n = 4), and tension-time integral was reduced by 57.81 +/- 2.6% (P = 0.006, n = 4). This ACPA effect was not statistically significant with respect to the reduction in tension in slow muscle fibers. Moreover, we detected the presence of mRNA for the cannabinoid CB(1) receptor on fast and slow skeletal muscle fibers, which was significantly higher in fast compared to slow muscle fiber expression. In conclusion, our results suggest that in the slow and fast muscle fibers of the frog cannabinoids diminish caffeine-evoked tension through a receptor-mediated mechanism.

Show MeSH
Related in: MedlinePlus