International Journal of Pharmacology1811-77751812-5700Asian Network for Scientific Information10.3923/ijp.2014.470.4782-Adrenoceptors on
Mydriasis]]>Raczak-GutknechtJoanna FrackowiakTeresa NasalAntoni RietzJoanna PaszekMaja Buszewska-ForajtaMagdalena KaliszanRoman 82014108The in vivo rat mydriasis model provides more information
on ligand-receptor interactions than in vitro studies. It allows assessment
which receptors (α2-adrenergic or imidazoline) participate in
mydriatic effect produced by imidazoline compounds, regarding the agonistic
and antagonistic properties and the strength of the reference ligands action.
The reference imidazoline agents can be tested within a wide range of doses,
in vivo in the animals. The experiments were performed to assess the
mydriatic effects of clonidine and rilmenidine with and without pretreatment
of rats with yohimbine, a reference α2-adrenoceptor antagonist.
Additionally, compound AGN 192403, regarded as a selective antagonist of I1-imidazoline
receptors was used in experiments. However, the previous data indicated that
AGN 192403 was devoid of both agonist and antagonist activity in some functional
assays. As a result of further investigation, AGN 192403 has been reported as
an antagonist to bind selectively at the I1 imidazoline binding site.
The α2-adrenomimetic potency of clonidine appeared to be stronger
than rilmenidine. Maximum mydriatic effect for clonidine and rilmenidine was
found at doses of 30 and 1000 μg kg-1, respectively. Yohimbine
administration caused parallel shift of the dose-effect curve for both rilmenidine
and clonidine to the right. Preliminary experiments with AGN 192403 seem to
confirm the hypothesis that the involvement of I1-imidazoline receptors
in mydriatic effects of imidazolines is marginal, if any. The present study
shows that rilmenidine has about 30 times weaker affinity to central α2-adrenoceptors
than clonidine. Yohimbine inhibits pupil dilation evoked by rilmenidine and
clonidine. That confirms the decisive role of α2-adrenoceptors
in mydriatic effect and suitability of the Rat Pupil Mydriasis Model for studies
of receptor selectivity of the centrally acting drugs.]]>Berridge, T.L., B. Gadie, A.G. Roach and I.F. Tulloch,19832-adrenoceptor agonists induce mydriasis in the rat by an action within the central nervous system.]]>78507515Brenner, G.M. and C.W. Stevens,20103rd Edn.,Calzada, B.C. and A.A. de Artinano,200144195208Christensen, H.D., M. Mutzig and M.C. Koss,19902-adrenoceptor induced mydriasis in conscious rats.]]>6123129Dardonville, C. and I. Rozas,200424639661Dziubdziela, W. and P. Jałowiecki,20022-adrenergic receptors and their agonists in anesthetic practice].]]>2135140, (In Polish)Ernsberger, P.,200035S27S41Ernsberger, P. and M.A. Haxhiu,1997273R1572R1579Feldman, J., H. Greney, L. Monassier, C. Vonthron, V. Bruban, M. Dontenwill and P. Bousquet,1998729497Gherezghiher, T. and M.C. Koss,197957263266Guyenet, P.G.,1997273R1580R1584Koss, M.C.,19862-adrenoceptor activation.]]>15119Koss, M.C.,20032‐adrenoceptors.]]>235156Koss, M.C. and L.C. San,197615566570Nasal, A., T. Frackowiak, J. Petrusewicz, A. Bucinski and R. Kaliszan,19952-adrenomimetics in comparison with other adrenoceptor-mediated effects and hydrophobicity.]]>274125132Stabile, A.M., H. Aceros, K. Stockmeyer, A.A.A. Rahman, N. Noiseux and S. Mukaddam-Daher,201188493503Szabadi, E. and C.M. Bradshaw,19962-adrenoceptors.]]>3618Szabo, B., T. Fritz and K. Wedzony,2001134295304Tolentino-Silva, F.P., M.A. Haxhiu, S. Waldbaum, I. Dreshaj and P. Ernsberger,20002-adrenergic receptors are not required for central anti-hypertensive action of moxonidine in mice.]]>8622635Van Zwieten, P.A., M.J. Thoolen and P.B. Timmermans,198462833Walland, A. and W. Kobinger,1971216165Yu, Y. and M.C. Koss,20051171724