A bizarre receptor mediating stimulatory effect of histamine on cyclic AMP formation in duck pineal gland

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• 作者：Nowak ; Jerzy Z. ; Sek ; Barbara ; Zawilska ; Jolanta B.
• 关键词：Duck pineal gland ; cAMP ; Histamine receptors
• 刊名：Neuroscience Letters
• 出版年：1995
• 出版时间：December 29, 1995
• 年：1995
• 卷：202
• 期：1-2
• 页码：65-68
• 全文大小：342 K

文摘

In agreement with our previous findings in chick pineal, histamine also appeared to be a potent stimulator of cAMP formation in intact duck pineal gland (about ten-fold increase above control at 100 μM), showing an EC₅₀ value of 3-5 μM. The effect of histamine in the duck pineal was mimicked by several histaminergic drugs, with the following order of potency: histamine = 4-methylhistamine > 2-methylhistamine > R-α-methylhistamine > amthamine > 2-thiazolylethylamine = immepip > imetit > dimaprit. The effect of 100 μM histamine was unaffected by H₁-, H₂- and H₃-receptor selective antagonists, mepyramine, ranitidine and thioperamide, respectively; yet, two other H₂-antagonists, aminopotentidine and tiotidine, reduced the histamine effect by only 40 % . Thus, these results, being in line with our previous chick data, give support to a suggestion that histamine may be considered a modulator of the pineal activity, and that the avian pineal may contain a novel or avian-specific histamine receptor modulating cAMP formation, whose pharmacology is different from that typical for H₁-, H₂-, or H₃-type receptor.