Possible Interaction: Agmatine and Yohimbine

“In contrast, pre‐treatment of &agr;2‐adrenoceptor antagonist, yohimbine (0.5&mgr;g/rat, icv) antagonized the memory enhancing effect of agmatine (20&mgr;g/rat, icv) in nicotine withdrawn rats.”

“ Yohimbine also blocked the hyperphagic effect elicited by ineffective dose combination of agmatine (5μg/rat, i.c.v.)”

“ Agmatine increased Akt and ERK phosphorylation and induced the transcription factor Nrf2 and the proteins HO-1 and GCLc; induction of these proteins was prevented by yohimbine , ketanserin, LY294002, and PD98059.”

“The central gastroprotective action of agmatine was completely antagonized by mixed alpha2-adrenoceptor and imidazoline I1 receptor antagonists (idazoxan, efaroxan), but only partially by yohimbine (selective alpha2-adrenoceptor antagonist) and AGN 192403 (selective I1 receptor ligand, putative antagonist).”

“Interestingly, the anticonvulsant effects of these effective combinations of lithium and agmatine were prevented by pre-treatment with low and non-effective doses of yohimbine [α(2)-adrenoceptor antagonist] (0.1 and 0.5mg/kg).”

“ Yohimbine pretreatment also suppressed agmatine induced restoration of blood pressure; however, the survival rate was found to be 17% for 3 min.”

“ Agmatine enhanced the antinociceptive effect of morphine, 2-BFI and BU224 and the enhancement was prevented by yohimbine , suggesting that the effect was mediated by α(2) adrenoceptors.”

“Conversely, prior administration of alpha(2)-adrenoceptor antagonist, yohimbine (5mg/kg, ip) or idazoxan (0.4 mg/kg, ip) reversed the inhibitory effect of agmatine on nicotine sensitization.”

“The effect of agmatine (40 mg x kg(-1), ig) was also antagonized by pindolol (20 mg x kg(-1), ip), yohimbine (5-10 mg x kg(-1), ip), or idazoxan (4 mg x kg(-1), ip).”

“While the effect of agmatine (6.4 micromol x L(-1)) was dose-dependently antagonized by pindolol (1 micromol x L(-1)) or yohimbine (0.25-1 micromol x L(-1)).”

“… agmatine (40 mg x kg(-1), ig) was antagonized by … mg x kg(-1), ip), alpha2-adrenergic receptor antagonists yohimbine (5-10 mg x kg(-1), ip) or idazoxan (4 mg x kg(-1), ip), …), ip) and 5-HT3 receptor antagonist tropisetron (5-40 mg x kg(-1), ip).”

“The effect of agmatine on the contractile responses to TAS was reversed by yohimbine , indicating involvement of alpha2 adrenoceptors in this response.”