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Re‐examination of role of α2‐adrenergic receptors in pithed rat pressor responses
Author(s) -
Docherty James R
Publication year - 2011
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.25.1_supplement.1021.4
Subject(s) - yohimbine , endocrinology , medicine , agonist , antagonist , chemistry , receptor , stimulation , alpha 2 adrenergic receptor , receptor antagonist , pharmacology
Yohimbine has been employed in a number of studies to identify α2‐adrenergic components to nerve and agonist induced pressor responses in the pithed rat. However, yohimbine has moderate affinity for α1D‐receptors and these have also been reported to mediate pressor nerve responses in the pithed rat. We have reexamined the actions of yohimbine in the pithed rat. Pressor nerve responses to 1 Hz stimulation were markedly inhibited by the α1A‐receptor antagonist RS 100329 (0.1 mg/kg) and by the α1D‐receptor antagonist BMY 7378 (0.1 mg/kg). Yohimbine (0.1 mg/kg) significantly increased, but yohimbine (1 mg/kg) significantly reduced, pressor nerve responses. Following BMY 7378 (0.1mg/kg), yohimbine (1 mg/kg) did not produce any further inhibition of pressor nerve responses. The α2A‐adrenoceptor antagonist BRL 44408 (1mg/kg) did not inhibit pressor nerve responses. Yohimbine or BRL 44408 (both 1mg/kg) significantly shifted, but BMY 7378 (1mg/kg) failed to affect, the pressor potency of the α2‐adrenergic agonist xylazine. Hence, responses to exogenous agonists in the pithed rat involve α2‐receptors but there is no clear evidence for the involvement of α2‐receptors in pressor nerve responses.