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Estrogen compromises the facilitatory effect of chronic nicotine on adenosine A 2B receptor/K + channel‐mediated renal vasodilations (837.3)
Author(s) -
ElMas Mahmoud,
ElGowilly Sahar,
Elsalakawy Lamia,
ElGowelli Hanan
Publication year - 2014
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.28.1_supplement.837.3
Subject(s) - nicotine , endocrinology , medicine , adenosine , chemistry , vasodilation , glibenclamide , estrogen , adenosine receptor , ovariectomized rat , phenylephrine , agonist , receptor , diabetes mellitus , blood pressure
We previously showed that the renal vasodilatory action of the adenosine analog 5’‐N‐ethyl carboxamidoadenosine (NECA) in female rats is mediated via adenosine A 2B receptors (A 2B Rs) and is facilitated by estrogen (E2). We tested the hypothesis that renal NECA vasodilation and its estrogen and A 2B R specificities are altered by chronic nicotine. Cumulative NECA (1.6–50 nmol) or papaverine (1‐243 nmol) vasodilations were not affected by nicotine (1‐8 mg/kg/day i.p., 2 weeks) in isolated phenylephrine‐preconstricted perfused kidneys of sham preparations. NECA, but not papaverine, vasodilations were reduced in kidneys of ovariectomized (OVX) rats and restored to near‐sham values after E2 replacement. Further, nicotine increased NECA vasodilations in OVX preparations in contrast to no effect in sham or OVXE2 kidneys. The enhanced NECA responsiveness in nicotine‐treated OVX preparations was abolished after the infusion of alloxazine (A 2B R antagonist) or BaCl 2 plus glibenclamide (blockers of inward rectifier and ATP‐sensitive K + channels, respectively). Moreover, vasodilations caused by minoxidil (K + ‐channel opener) were increased by nicotine in OVX, but not sham or OVXE2, preparations and this increase was abolished after BaCl 2 /glibenclamide infusion. Together, estrogen compromises the enhancing effect of nicotine on renal vasodilations evoked via the activation of the A 2B R/K + channel cascade. Grant Funding Source : Supported by STDF ID 502, Egypt