Abstract
We examined the effect of N-methyltyramine (NMT) on alpha2-adrenoceptor. NMT (10(-8)-10(-3) M) inhibited the binding of [3H]p-aminoclonidine to alpha2-adrenoceptor dose-dependently. However, the IC50 value for NMT (5.53 x 10(-6) M) was higher than that for RX821002, an alpha2-adrenoceptor antagonist (1.07 x 10(-8) M). RX821002 (5 mg/kg, i.p.) inhibited hypermotility induced by scopolamine (8 mg/kg, s.c.) in male ddY mice. NMT (20 or 100 mg/kg, i.p.) was found to have a dose-dependent inhibitory effect similar to that of RX821002. These findings indicate that NMT has the properties of an alpha2-adrenoceptor antagonist. However, the affinity of NMT for alpha2-adrenoceptor is weaker than that of RX821002.
MeSH terms
-
Adrenergic alpha-2 Receptor Antagonists*
-
Adrenergic alpha-Agonists / metabolism
-
Adrenergic alpha-Agonists / pharmacology
-
Adrenergic alpha-Antagonists / metabolism
-
Adrenergic alpha-Antagonists / pharmacology*
-
Animals
-
Clonidine / analogs & derivatives
-
Clonidine / metabolism
-
Clonidine / pharmacology
-
Idazoxan / analogs & derivatives
-
Idazoxan / metabolism
-
Idazoxan / pharmacology
-
Male
-
Mice
-
Radioligand Assay
-
Receptors, Adrenergic, alpha-2 / metabolism
-
Scopolamine / antagonists & inhibitors
-
Scopolamine / pharmacology
-
Tyramine / analogs & derivatives*
-
Tyramine / metabolism
-
Tyramine / pharmacology
Substances
-
Adrenergic alpha-2 Receptor Antagonists
-
Adrenergic alpha-Agonists
-
Adrenergic alpha-Antagonists
-
Receptors, Adrenergic, alpha-2
-
apraclonidine
-
Scopolamine
-
2-methoxyidazoxan
-
methyl-4-tyramine
-
Clonidine
-
Tyramine
-
Idazoxan