Adenosine A 3 receptors regulate heart rate, motor activity and body temperature

• Published in: Acta Physiologica Vol. 199; no. 2; pp. 221 - 230
• Main Authors: Yang, J. N., Wang, Y., Garcia‐Roves, P. M., Björnholm, M., Fredholm, B. B.
• Format: Journal Article
• Language: English
• Published: 01.06.2010
• ISSN: 1748-1708; 1748-1716
• DOI: 10.1111/j.1748-1716.2010.02091.x

Abstract Aim:  To examine the phenotype of mice that lack the adenosine A 3 receptor (A 3 R). Methods:  We examined the heart rate, body temperature and locomotion continuously by telemetry over several days. In addition, the effect of the adenosine analogue R‐ N 6 ‐phenylisopropyl‐adenosine (R‐PIA) was examined. We also examined heat production and food intake. Results:  We found that the marked diurnal variation in activity, heart rate and body temperature, with markedly higher values at night than during day time, was reduced in the A 3 R knock‐out mice. Surprisingly, the reduction in heart rate, activity and body temperature seen after injection of R‐PIA in wild type mice was virtually eliminated in the A 3 R knock‐out mice. The marked reduction in activity was associated with a decreased heat production, as expected. However, the A 3 R knock‐out mice, surprisingly, had a higher food intake but no difference in body weight compared to wild type mice. Conclusions:  The mice lacking adenosine A 3 receptors exhibit a surprisingly clear phenotype with changes in diurnal rhythm and temperature regulation. Whether these effects are due to a physiological role of A 3 receptors in these processes or whether they represent a role in development remains to be elucidated.