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Clonidine and benazoline are two structurally related imidazolines. Whereas clonidine binds both to alpha(2)-adrenoceptors (alpha(2)R) and to I(1) imidazoline receptors (I(1)R), benazoline showed a high selectivity for imidazoline receptors. Although the alpha(2)R are negatively coupled to adenylate cyclase, no effect on cAMP level by activation of I(1)R(More)
The efficacy and affinity of nine pentatomic cyclic muscarinic agonists were determined on the guinea-pig ileum, according to the method of Furchgott & Bursztyn (1967). The efficacy and affinity of these agonists are affected differently by structural modifications. Our results suggest that a strong dipole oriented in the same direction as that of the(More)
Age-dependent changes in the expression of muscarinic M1 and M2 cholinergic receptors were assessed in the CA1 and CA3 fields of hippocampus using radioligand binding and autoradiographic techniques with [3H]-pirenzepine and [3H]-AF-DX 116 as ligands. Male Wistar rats of 2 months (young), 12 months (adult) and 27 months (old) of age were examined.(More)
To assess the stereochemical requirements for efficient alpha2C-adrenoreceptor activation, the enantiomeric forms of m-nitrobiphenyline [(+/-)-5] were prepared and tested on cells expressing the human alpha2-adrenoreceptor subtypes. The importance of chirality was confirmed, since the enantiomer (R)-(+)-5 was much more efficient than (S)-(-)-5 in producing(More)
Racemate and corresponding enantiomers of muscarinic agonists carrying a 1,3-oxathiolane nucleus were studied on isolated preparations of guinea-pig ileum and atria and of rat urinary bladder. The efficacy of these agonists were determined according to the method of Furchgott and Bursztyn (1967) and enantio-selectivity and tissue-selectivity were(More)
The potent cholinergic agonist (+/-)-cis-2-methyl-5-[(dimethylamino)methyl]-1,3-oxathiolane methiodide (+/-)-1] was resolved into enantiomeric forms. Their absolute configurations were established by a synthetic pathway that also allowed the synthesis of the corresponding diastereomeric (+)- and (-)-trans-2-methyl-5-[(dimethylamino)-methyl]-1,3-oxathiolane(More)
A total of 20 substituted analogues of nicotine (1a) and homoazanicotine (3a) were examined in order to determine whether or not they might bind in a similar manner at alpha4beta2 nicotinic acetylcholinergic (nACh) receptors. It was found that parallel structural changes in the two series resulted in parallel shifts in affinity. Evidence suggests that the(More)
This study demonstrated that cyclomethyline (2) and the corresponding enantiomers (R)-(-)-2 and (S)-(+)-2, displaying α2C-adrenoreceptor (AR) agonism/α2A-AR antagonism, similarly to allyphenyline (1) and its enantiomers, significantly decreased the naloxone-precipitated withdrawal symptoms in mice at very low doses. It also highlighted that such positive(More)
The imidazoline nucleus linked in position 2 via an oxyethylene bridge to a phenyl ring carrying an ortho substituent of moderate steric bulk provided alpha(2)-adrenergic (AR) ligands endowed with significant alpha(2C)-agonism/alpha(2A)-antagonism. Similar behavior was displayed by cirazoline (12). For their positive morphine analgesia modulation (due to(More)
The goal of the present study was to modulate the receptor interaction properties of known alpha 2-adrenoreceptor (AR) antagonists to obtain novel alpha 2-AR agonists with desirable subtype selectivity. Therefore, a phenyl group or one of its bioisosteres or aliphatic moieties with similar steric hindrance were introduced into the aromatic ring of the(More)