1,721,003 research outputs found
Ruolo dei recettori tachichininici NK2 nella contrazione della muscolatura liscia circolare dell'ileo di cavallo
No full textAdrenergic regulation of vascular smooth muscle tone in calf digital artery
No full textRadioligand binding studies and functional assays on isolated smooth muscle
preparations were performed in order to obtain a biochemical and functional
characterization of the b-adrenoceptor (b-AR) subtypes involved in regulation
of the smooth muscle relaxation of the calf’s common digital artery. The results
indicate that the common digital artery possesses two b-AR populations (40%
b1 and 60% b2) and the b2-subtype appears to predominate as far as function is
concerned. Only the b2-AR agonists clenbuterol and fenoterol caused doserelated
relaxant effects, antagonized by propranolol, when tested in preparations
precontracted both with PGF2a (1.4 · 10)5
M) and noradrenaline
(1.2 · 10)6
M). In noradrenaline precontracted preparations the b1-AR
selective agonists dobutamine and xamoterol caused vasodilation which was
not antagonized by (±)propranolol. While the functional relaxant effects of
dobutamine may be attributed to its potent competitive a-AR blocking activity,
further investigations are required to explain the effect of xamoterol. The
vasodilator effect of (±)isoproterenol was irregular. The recorded contractile
effects, mainly at dosages greater than 10)6
M, suggest the loss of drug
selectivity for b-AR and a-AR activation. Indirect evidence indicates that the aadrenoceptor
(a-AR) population in this tissue which produces a strong
contraction is functionally dominant over the b-AR, suggesting limited
therapeutic benefit for b-AR drugs to control blood flow disorders in the calf’s
distal limb
Suitability of the old fowl rectal caecum preparation for investigating the selectivity of beta-adrenergic drugs
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Recettori adrenergici coinvolti nell'effetto vasodilatante dell'isossisuprina sull'arteria digitale comune di cavallo
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Effetti della Dermorfina sulla motilità gastroenterica della pecora: osservazioni preliminari.
No full textIdentificazione dei ß-recettori coinvolti nella lipolisi nel tessuto adiposo sottocutaneo di vitello
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