Article date: May 1993
By: J.R. Fozard, A.M. Carruthers, in Volume 109, Issue 1, pages 3-5
The cardiovascular effects of N6‐2‐(4‐aminophenyl)ethyladenosine (APNEA), which when radiolabelled with 125I shows high affinity for the newly described adenosine A3 receptor, have been investigated in the angiotension II‐supported circulation of the pithed rat. APNEA induces hypotensive responses which are unaffected by high doses (20–40 mg kg−1) of the broad spectrum, adenosine receptor antagonist, 8‐(p‐sulphophenyl)theophylline (8‐SPT). 8‐SPT‐resistant falls in blood pressure are also seen, in the absence of bradycardia, with 5′‐N‐ethylcarboxamidoadenosine (NECA) and the R‐ and S‐enantiomers of N6‐phenylisopropyladenosine (PIA). Xanthine insensitivity, high potencies of APNEA, NECA and R‐PIA, and an enantiomeric selectivity favouring R‐ over S‐PIA are distinguishing features of the adenosine A3 receptor. We suggest that hypotension in the pithed rat may be a functional correlate of this site.
DOI: 10.1111/j.1476-5381.1993.tb13522.x
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