Department of Biophysics, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
Neurosci Res. 2013 May-Jun;76(1-2):31-41. doi: 10.1016/j.neures.2013.03.001. Epub 2013 Mar 15.
Egg-laying behavior in Aplysia is accompanied by behavioral changes such as feeding suppression. We investigated the effects of the egg-laying hormone (ELH) on food intake, the activity patterns of jaw muscles, and the activity of buccal neurons (multi-action neuron [MA1] and jaw-closing motor neuron [JC2]), which are elements of the feeding neural circuits controlling jaw movements in Aplysia kurodai. Injection of ELH into the body cavity inhibited the intake of seaweed. After ELH application, the rhythmic activity of jaw muscles that was induced by preferred taste stimulation elicited fewer ingestion-like responses and increased the number of rejection-like responses. ELH applied to the buccal ganglia increased the firing activity of JC2 during spontaneous rhythmic responses and during the rhythmic feeding-like responses that were evoked by electrical stimulation of the esophageal nerves. In the 2 types of rhythmic responses, the Dn (normalized value of the delay time of JC2 firing onset) decreased after ELH application as compared with the control. Furthermore, ELH decreased the size of MA1-induced inhibitory postsynaptic currents in JC2. These results suggest that ELH changes the buccal motor program from ingestion to rejection on the basis of our previous results, and may contribute to a decrease in food intake during egg laying.
产卵行为伴随着行为改变，如摄食抑制。我们研究了产卵激素（ELH）对食物摄入、颚肌活动模式以及参与控制颚运动的摄食神经回路的咀嚼神经元（多动作神经元[MA1]和闭口运动神经元[JC2]）活动的影响。在黑侧褶鲍中，将 ELH 注射到体腔中会抑制海藻的摄入。在 ELH 应用后，由偏好味觉刺激引起的颚肌节律活动引起的摄取样反应减少，而排斥样反应增加。ELH 应用于口腔神经节会增加 JC2 在自发节律反应和食管神经电刺激诱发的节律摄食样反应期间的放电活动。在这 2 种节律反应中，与对照相比，ELH 应用后 Dn（JC2 放电起始延迟时间的归一化值）降低。此外，ELH 减小了 MA1 在 JC2 中诱导的抑制性突触后电流的大小。这些结果表明，ELH 根据我们之前的结果将口腔运动程序从摄取转变为排斥，这可能有助于产卵期间食物摄入的减少。
