Postnatal differentiation of local networks in the nucleus of the tractus solitarius.
Whole-cell voltage-clamp recordings from rat brain slice preparation were used to investigate a possible developmental change in the patterns of synaptic interactions among the nucleus tractus solitarii neurons by analysing spontaneous postsynaptic current activity. Three types of patterns of spontaneous postsynaptic current activity were distinguished in the nucleus tractus solitarii neurons which showed high activities in terms of current frequency and amplitude. The first type was characterized by the presence in an individual cell of high frequencies and large amplitudes of both spontaneous glutamatergic and GABAergic postsynaptic currents, and observed exclusively in postnatal day 0-7 rats. The second and third types of cells showed predominant either inhibitory or excitatory postsynaptic currents, respectively. After postnatal day 5, nucleus tractus solitarii neurons with high background activity were shown to differentiate into either the second or the third type, with the latter of about 70% in the adult caudal/intermediate nucleus tractus solitarii. Axon collaterals of some medium to large neurons seemed to be decreased by pruning during postnatal development. The early postnatal differentiation of background synaptic activity observed in the nucleus tractus solitarii presumably reflects the local network reorganization and may be related to maturational changes in cardiovascular and respiratory functions.
Kawai
Y
Y
Department of Anatomy and Neurobiology, Wakayama Medical College, 811-1 Kimiidera, 641-8509, Wakayama, Japan. ykawai@wakayama-med.ac.jp
Senba
E
E
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development*; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D018698:Glutamic Acid / Q000502:physiology; D066298:In Vitro Techniques; D009415:Nerve Net / Q000254:growth & development*; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D017552:Solitary Nucleus / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D013569:Synapses / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid