Optogenetic activation of GnRH neurons reveals minimal requirements for pulsatile luteinizing hormone secretion
Optogenetic activation of GnRH neurons reveals minimal requirements for pulsatile luteinizing hormone secretion
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DOI：
10.1073/pnas.1415226112
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发表时间：
2014-12-23
影响因子：
11.1
通讯作者：
Herbison, Allan E.
中科院分区：
文献类型：
--
作者：
Campos, Pauline;Herbison, Allan E.
垂体产生促性腺激素脉冲释放的机制尚不清楚。我们在这里开发了一种方法，在小鼠体内控制促性腺激素释放激素（GnRH）神经元的活性，以建立最小的激活参数，引起脉冲的促黄体激素（LH）分泌。将Cre依赖性通道视紫红质（ChR 2）携带腺相关病毒注射入成年GnRH-Cre小鼠正中隆起，导致ChR 2在垂体促性腺激素释放激素神经元中的选择性表达。急性脑切片实验表明，表达ChR 2的GnRH神经元可以被驱动以高尖峰保真度发射，蓝光刺激频率高达40 Hz，持续数秒，高达10 Hz，持续数分钟。麻醉，卵巢切除小鼠的光学纤维植入在附近的GnRH神经元的吻侧视前区。GnRH神经元在不同频率范围内的30秒至5分钟时间段的光遗传激活显示，10 Hz刺激2分钟是产生LH脉冲样增量所需的最低限度。正中隆起的GnRH投射的光学激活也发现了相同的结果。LH分泌的增加与从卵巢切除小鼠测量的内源性LH脉冲参数进行比较。驱动GnRH神经元表现出同时爆发放电在改变LH分泌方面是无效的。这些观察结果提供了一个深入了解GnRH神经元如何产生脉冲式LH分泌体内。
The mechanisms responsible for generating the pulsatile release of gonadotropins from the pituitary gland are unknown. We develop here a methodology in mice for controlling the activity of the gonadotropin-releasing hormone (GnRH) neurons in vivo to establish the minimal parameters of activation required to evoke a pulse of luteinizing hormone (LH) secretion. Injections of Cre-dependent channelrhodopsin (ChR2)-bearing adeno-associated virus into the median eminence of adult GnRH-Cre mice resulted in the selective expression of ChR2 in hypophysiotropic GnRH neurons. Acute brain slice experiments demonstrated that ChR2-expressing GnRH neurons could be driven to fire with high spike fidelity with bluelight stimulation frequencies up to 40 Hz for periods of seconds and up to 10 Hz for minutes. Anesthetized, ovariectomized mice had optical fibers implanted in the vicinity of GnRH neurons within the rostral preoptic area. Optogenetic activation of GnRH neurons for 30-s to 5-min time periods over a range of different frequencies revealed that 10 Hz stimulation for 2 min was the minimum required to generate a pulse-like increment of LH. The same result was found for optical activation of GnRH projections in the median eminence. Increases in LH secretion were compared with endogenous LH pulse parameters measured from ovariectomized mice. Driving GnRH neurons to exhibit simultaneous burst firing was ineffective at altering LH secretion. These observations provide an insight into how GnRH neurons generate pulsatile LH secretion in vivo.