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Activation Of Adenosine A 2A Receptors Causes Hypotension In Newborn But Not Adult Rats
Author(s) -
ABUSHAWEESH JALAL M
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.977.2
Subject(s) - adenosine , medicine , adenosine receptor , cgs 21680 , adenosine a1 receptor , agonist , endocrinology , blood pressure , receptor , heart rate , adenosine a2a receptor , anesthesia
Hypotension is very common in premature infants and has been associated with poor neurodevelopmental outcome although the underlying pathophysiology is unclear. Activation of central adenosine A 2A receptors in decerebrate, vagotomized newborn piglets caused hypotension. We hypothesized that over‐expression of adenosine A 2A receptors predisposes newborns to hypotension. We aimed to test this hypothesis by examining the effect of intraperitoneal injection (IP) of adenosine A 2A receptor agonist CGS 21680 (CGS) on blood pressure (BP) in awake, non‐restrained maturing rats. BP was measured using a non‐invasive cuff blood pressure system, sphygmomanometery, on rat tail (PanLab, Spain). After 30 minutes of acclimatization in appropriate size chambers BP was measured before and one hour after IP CGS (4 mg/kg). CGS caused a significant decrease in systolic and diastolic BP in animals up to 6 weeks of life (n=13) but not adult rats (n=2). The systolic and diastolic BP decreased from 118±4 and 83±3 mmHg before CGS to 96±5 and 65±3 mmHg after CGS, respectively, p <0.001. Additionally, CGS caused a significant increase in heart rate from 426±7 to 528±14 before and after CGS, respectively, p < 0.001. We conclude that activation of adenosine A 2A receptors causes hypotension in young but not adult rats. We speculate that over‐expression of adenosine A 2A receptors early in life predisposes preterm infants to hypotension.