Neuropeptide Y modulates membrane excitability in neonatal rat mesencephalic V neurons

• Published in: Journal of neuroscience research 2020-05, Vol.98 (5), p.921-935
• Main Authors: Seki, Soju, Tanaka, Susumu, Yamada, Saori, Tsuji, Tadataka, Enomoto, Akifumi, Ono, Yudai, Chandler, Scott H., Kogo, Mikihiko
• Format: Article
• Language: English
• Subjects: Action potential; Afterhyperpolarization; Brain slice preparation; Current injection; Depolarization; Discharge; Excitability; Feeding; Feeding behavior; Feeding rates; Food intake; Grooming; Intracerebroventricular administration; Jaw; Mastication; Membrane potential; Membranes; mesencephalic trigeminal neuron; Neonates; Neurons; Neuropeptide Y; Neuropeptides; oral motor activity; patch clamp; Proprioception; Receptors; Reflexes; Rodents; Sensory neurons
• ISSN: 0360-4012; 1097-4547
• DOI: 10.1002/jnr.24583

Neuropeptide Y (NPY) is one of a number of neuropeptides with powerful orexigenic effects. Intracerebroventricular administration of NPY induces increases in food intake and alters feeding rate. Besides it role in feeding behavior, NPY also has significant effects on neuronal systems related to other spontaneous behaviors such as rearing and grooming. In the present study, we examined the direct effects of NPY on mesencephalic V neurons (Mes V), which are important sensory neurons involved in oral motor reflexes and rhythmical jaw movements, as well as masticatory proprioception. Coronal brain slices were prepared from neonatal Sprague‐Dawley rats (P3‐17) and whole‐cell patch clamp recordings were obtained from Mes V neurons. Bath application of NPY depolarized the membrane potential and induced inward current in most neurons. Application of NPY shortened the duration of the afterhyperpolarization following an action potential, and increased the mean spike frequency during repetitive discharge. In those neurons which exhibited rhythmical burst discharge in response to maintained current injection, the bursting frequency was also increased. These effects were mediated predominately by both Y1 and Y5 receptors. Neuropeptide Y (NPY) facilitates spontaneous bursting discharge produced by a constant depolarizing current stimulus accompanying with increase of intra‐burst frequency in mesencephalic V neuron (a). Facilitation of persistent sodium current activation and modulation of channel gating by NPY are potentially involved in those effects (b,c).