N-methyl-D-aspartate triggers neonatal rat hypoglossal motoneurons in vitro to express rhythmic bursting with unusual Mg2+ sensitivity.

The brainstem nucleus hypoglossus innervates the tongue which must contract rhythmically during respiration, chewing and swallowing. Such rhythmic discharges are due to network bursting mediated by AMPA receptor-dependent glutamatergic transmission. The contribution by hypoglossal motoneurons themselves to rhythmicity remains, however, unclear as they might simply express cyclic patterns produced by premotoneurons or, in analogy to spinal motoneurons, might participate to bursting due to activation of their N-methyl-D-aspartate (NMDA) receptors.

Modeling study of mecamylamine block of muscle type acetylcholine receptors.

The blocking action of mecamylamine on different types of nicotinic acetylcholine receptors (nAChRs) has been extensively studied and used as a tool to characterize the nAChRs from different synapses. However, mechanism of mecamylamine action was not fully explored for all types of nAChRs. In the present study, we provide brief description of the mecamylamine action on muscle nAChRs expressed at the frog neuromuscular junction.

A new stochastic tridimensional model of neonatal rat spinal motoneuron for investigating compartmentalization of neuronal conductances and their influence on firing.

During postnatal development spinal motoneurons play a major role in expressing basic behaviours like reflex reactions and in allowing the onset of the locomotor programme. For this purpose it is useful to clarify how various inputs are integrated at the level of the motoneuron soma to generate phasic or rhythmic firing. Although existing models of motoneurons have indicated the distributed role of certain conductances in regulating firing, it is unclear how the spatial distribution of certain currents is ultimately shaping motoneuron output.

The effects induced by the sulphonylurea glibenclamide on the neonatal rat spinal cord indicate a novel mechanism to control neuronal excitability and inhibitory neurotransmission.

Background And Purpose: Using the neonatal rat spinal cord in vitro, we investigated the action of glibenclamide, a drug possessing dual pharmacological effects, namely block of K(ATP) channels and of the cystic fibrosis transmembrane conductance regulator (CFTR).

Experimental Approach: Intra- and extracellular recordings were performed on motoneurons and interneurons. RT-PCR and western immunoblotting were used to determine gene and protein expression.

Tuning and playing a motor rhythm: how metabotropic glutamate receptors orchestrate generation of motor patterns in the mammalian central nervous system.

Repeated motor activities like locomotion, mastication and respiration need rhythmic discharges of functionally connected neurons termed central pattern generators (CPGs) that cyclically activate motoneurons even in the absence of descending commands from higher centres. For motor pattern generation, CPGs require integration of multiple processes including activation of ion channels and transmitter receptors at strategic locations within motor networks. One emerging mechanism is activation of glutamate metabotropic receptors (mGluRs) belonging to group I, while group II and III mGluRs appear to play an inhibitory function on sensory inputs.