Chemogenetic tools such as designer receptors exclusively activated by designer drugs (DREADDs) are routinely used to modulate neuronal and non-neuronal signaling and activity in a relatively noninvasive manner. The first generation of DREADDs were templated from the human muscarinic acetylcholine receptor family and are relatively insensitive to the endogenous agonist acetylcholine but instead are activated by clozapine-N-oxide (CNO). Despite the undisputed success of CNO as an activator of muscarinic DREADDs, it has been known for some time that CNO is subject to a low rate of metabolic conversion to clozapine, raising the need for alternative chemical actuators of muscarinic-based DREADDs. Here we show that DREADD agonist 21 (C21) (11-(1-piperazinyl)-5H-dibenzo[b,e][1,4]diazepine) is a potent and selective agonist at both excitatory (hM3Dq) and inhibitory (hM4Di) DREADDs and has excellent bioavailability, pharmacokinetic properties, and brain penetrability. We also show that C21-induced activation of hM3Dq and hM4Di in vivo can modulate bidirectional feeding in defined circuits in mice. These results indicate that C21 represents an alternative to CNO for in vivo studies where metabolic conversion of CNO to clozapine is a concern.

中文翻译：

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DREADD 激动剂 21 是体外和体内基于毒蕈碱的 DREADD 的有效激动剂。

化学遗传学工具，例如专门由设计药物 (DREADD) 激活的设计受体，通常用于以相对无创的方式调节神经元和非神经元信号传导和活动。第一代 DREADD 以人毒蕈碱乙酰胆碱受体家族为模板，对内源性激动剂乙酰胆碱相对不敏感，而是被氯氮平-N-氧化物 (CNO) 激活。尽管 CNO 作为毒蕈碱 DREADD 的激活剂取得了无可争议的成功，但一段时间以来众所周知，CNO 代谢转化为氯氮平的速率较低，因此需要替代基于毒蕈碱的 DREADD 的化学驱动器。在这里，我们展示了 DREADD 激动剂 21 (C21) (11-(1-piperazinyl)-5H-dibenzo[b,e][1, 4] diazepine) 是兴奋性 (hM3Dq) 和抑制性 (hM4Di) DREADD 的有效选择性激动剂，具有出色的生物利用度、药代动力学特性和脑渗透性。我们还表明，C21 诱导的体内 hM3Dq 和 hM4Di 激活可以调节小鼠定义电路中的双向喂养。这些结果表明 C21 代表了 CNO 的替代品，用于体内研究，其中 CNO 代谢转化为氯氮平是一个问题。