神经肽调节通过双网络神经元实现网络间的双相协调。
Neuropeptide Modulation Enables Biphasic Internetwork Coordination via a Dual-Network Neuron.
机构信息
Department of Biology, Center for Neuroscience and Behavior, Miami University, Oxford, Ohio 45056.
Department of Biology, Center for Neuroscience and Behavior, Miami University, Oxford, Ohio 45056
出版信息
eNeuro. 2024 Jun 27;11(6). doi: 10.1523/ENEURO.0121-24.2024. Print 2024 Jun.
Linked rhythmic behaviors, such as respiration/locomotion or swallowing/chewing, often require coordination for proper function. Despite its prevalence, the cellular mechanisms controlling coordination of the underlying neural networks remain undetermined in most systems. We use the stomatogastric nervous system of the crab to investigate mechanisms of internetwork coordination, due to its small, well-characterized feeding-related networks (gastric mill [chewing, ∼0.1 Hz]; pyloric [filtering food, ∼1 Hz]). Here, we investigate coordination between these networks during the Gly-SIFamide neuropeptide modulatory state. Gly-SIFamide activates a unique triphasic gastric mill rhythm in which the typically pyloric-only LPG neuron generates dual pyloric-plus gastric mill-timed oscillations. Additionally, the pyloric rhythm exhibits shorter cycles during gastric mill rhythm-timed LPG bursts, and longer cycles during IC, or IC plus LG gastric mill neuron bursts. Photoinactivation revealed that LPG is necessary to shorten pyloric cycle period, likely through its rectified electrical coupling to pyloric pacemaker neurons. Hyperpolarizing current injections demonstrated that although LG bursting enables IC bursts, only gastric mill rhythm bursts in IC are necessary to prolong the pyloric cycle period. Surprisingly, LPG photoinactivation also eliminated prolonged pyloric cycles, without changing IC firing frequency or gastric mill burst duration, suggesting that pyloric cycles are prolonged via IC synaptic inhibition of LPG, which indirectly slows the pyloric pacemakers via electrical coupling. Thus, the same dual-network neuron directly conveys excitation from its endogenous bursting and indirectly funnels synaptic inhibition to enable one network to alternately decrease and increase the cycle period of a related network.
关联的节律行为,如呼吸/运动或吞咽/咀嚼,通常需要协调以正常运作。尽管它很普遍,但大多数系统中控制潜在神经网络协调的细胞机制仍未确定。我们使用蟹的口胃神经系统来研究网络间协调的机制,因为它的与进食相关的小而特征明确的网络(咀嚼胃神经节[chewing,∼0.1 Hz];过滤食物的幽门神经节[pyloric,∼1 Hz])。在这里,我们研究了在甘氨酸-SIF 酰胺神经肽调制状态下这些网络之间的协调。甘氨酸-SIF 酰胺激活了独特的三相胃神经节节律,其中典型的仅幽门神经元产生双重幽门加胃神经节定时振荡。此外,在胃神经节节律定时 LPG 爆发期间,幽门节律的周期更短,而在 IC 或 IC 加 LG 胃神经节神经元爆发期间,周期更长。光失活表明 LPG 对于缩短幽门周期是必要的,可能是通过其对幽门起搏神经元的整流电耦合。超极化电流注入表明,尽管 LG 爆发使 IC 爆发成为可能,但只有在 IC 中胃神经节节律爆发才会延长幽门周期。令人惊讶的是,LPG 光失活也消除了延长的幽门周期,而不会改变 IC 放电频率或胃神经节爆发持续时间,这表明通过 IC 对 LPG 的突触抑制延长了幽门周期,这间接通过电耦合减缓了幽门起搏神经元。因此,相同的双网络神经元直接传递其自身爆发的兴奋,间接将突触抑制引导到相关网络,从而使一个网络交替地减少和增加相关网络的周期。