Age-dependent changes in adenosine A1 receptor distribution and density within the nucleus tractus solitarii of normotensive and hypertensive rats.

This study shows the distribution and density of adenosine A1 receptor (A1R) within the nucleus tractus solitarii (NTS) of Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) from birth to adulthood (1, 15, 30 and 90 days old). The NTS shows heterogeneous distribution of A1R in dorsomedial/dorsolateral, subpostremal and medial/intermediate subnuclei. A1R decrease from rostral to caudal within dorsomedial/dorsolateral subnucleus in 15-, 30- and 90-day-old WKY and SHR. A1R increase from rostral to caudal subpostremal subnucleus in 30- and 90-day-old WKY, and in 15-, 30- and 90-day-old SHR. Furthermore, A1Rs are increased in SHR as compared with WKY within dorsomedial/dorsolateral in 30- and 90-day-old and within subpostremal of 15-, 30- and 90-day-old rats. Finally, A1Rs increase from 1- to 30-day-old rats. Medial/intermediate did not show any changes in A1R from rostral to caudal levels, age or strain. In summary, our result highlights the importance of A1 adenosine system regarding the neural control of blood pressure and the development of hypertension.