FMRFamide-related peptide expression in the vestibular-afferent neurons.

Vestibular-afferent neurons innervate hair cells from the sensory epithelia of vestibular end-organs and their action-potential discharge dynamics are driven by linear and angular accelerations of the head. The electrical activity of the vestibular-afferent neurons depends on their intrinsic properties and on the synaptic input from hair cells and from the terminals of the efferent system. Here we report that vestibular-afferent neurons of the rat are immunoreactive to RFamide-related peptides, and that the stronger signal comes from calyx-shaped neuron dendrites, with no signal detected in hair cells or supporting cells. The whole-cell voltage clamp recording of isolated afferent neurons showed that they express robust acid-sensing ionic currents (ASICs). Extracellular multiunit recordings of the vestibular nerve in a preparation in vitro of the rat inner ear showed that the perfusion of FMRFamide (a snail ortholog of this family of neuropeptides) exerts an excitatory effect on the afferent-neurons spike-discharge rate. Because the FMRFamide cannot activate the ASIC but reduces its desensitization generating a more robust current, its effect indicates that the ASIC are tonically active in the vestibular-afferent neurons and modulated by RFamide-like peptides.

Facilitadores y consecuentes del aprendizaje de equipo: apuntes para futuras investigaciones

El aprendizaje ha sido destacado como uno de los pilares fundamentales de la organización (Senge, 1990) y especialmente en los momentos actuales, de incertidumbre y cambio. Como señalan Alcover y Gil (2002) ‘La capacidad para aprender más, y de hacerlo más deprisa que las demás organizaciones, se convierte en la principal, y quizás la única ventaja competitiva sostenible, y por tanto la razón de subsistencia’. El aprendizaje tiene lugar en distintos niveles; además del aprendizaje individual, resulta fundamental el aprendizaje colectivo, tanto organizacional, como de equipo. En relación al aprendizaje de equipo, los investigadores se han centrado en analizar, partiendo de los trabajos pioneros de Edmondson (1999), por una parte los principales factores que influyen en dicho aprendizaje y en segundo lugar la influencia del mismo en los resultados de los equipos. Este artículo tiene un doble objetivo. Primero, sintetizar e integrar las definiciones de aprendizaje de equipo, entendido éste tanto como proceso y como resultado. Segundo, analizar las principales variables antecedentes y de resultado de la investigación actual sobre aprendizaje de equipo.(AU)

Facilitadores y consecuentes del aprendizaje de equipo: apuentes para futuras investigaciones / Facilitators and consequences of team learning: Notes for future investigations

El aprendizaje ha sido destacado como uno de los pilares fundamentales de la organización (Senge, 1990) y especialmente en los momentos actuales, de incertidumbre y cambio. Como señalan Alcover y Gil (2002) 'La capacidad para aprender más, y de hacerlo más deprisa que las demás organizaciones, se convierte en la principal, y quizás la única ventaja competitiva sostenible, y por tanto la razón de subsistencia'. El aprendizaje tiene lugar en distintos niveles; además del aprendizaje individual, resulta fundamental el aprendizaje colectivo, tanto organizacional, como de equipo. En relación al aprendizaje de equipo, los investigadores se han centrado en analizar, partiendo de los trabajos pioneros de Edmondson (1999), por una parte los principales factores que influyen en dicho aprendizaje y en segundo lugar la influencia del mismo en los resultados de los equipos. Este artículo tiene un doble objetivo. Primero, sintetizar e integrar las definiciones de aprendizaje de equipo, entendido éste tanto como proceso y como resultado. Segundo, analizar las principales variables antecedentes y de resultado de la investigación actual sobre aprendizaje de equipo.

The learning has been highlighted as one of the main pillars of the organization (Senge, 1990) and especially in the present time of uncertainty and change. As Alcover and Gil (2002) affirm, the 'capacity to learn more, and make it more quickly than the other organizations becomes the main, and perhaps only sustainable competitive advantage, and therefore the reason for subsistence'. The learning takes place at various levels; in addition to the individual learning, it is essential the collective learning, both organizational, and team. In relation to the learning of teams, researchers have focused on analyze, on the basis of the pioneering work of Edmondson (1999), first in what concerns the main factors that influence such learning and secondly the influence of the same in the results of the teams. This article has a dual purpose. First, to synthesize and integrate the definitions of team learning, understood that as a process and as a result. Second, to analyze the main background and outcoming variables of the current research on team learning.

[Morphologic and electrophysiologic characteristics of cultured vestibular ganglia neurons]. / Características morfológicas y electrofisiológicas de las neuronas del ganglio vestibular en cultivo.

Vestibular afferent neurons have been classified on the basis of their spontaneous activity as regular and irregular; this has been attributed to their synaptic input, but it remains to be defined the participation of some intrinsical properties of the afferent neurons in the determination of their discharge pattern. In this work, we have developed tissue cultures of the rat vestibular ganglia. Isolated cells were plated using poly-D-lysine or collagen as substrates and L-15 or Neurobasal as culture media. After 48 hrs cells in the four experimental conditions give forth neurites of variable longitude. By using antibodies against the neurofilaments 160 kDa the cell structure was studied. Monopolar (30.6%), bipolar (63.9%) and multipolar (5.5%) cells were found. By using the voltage and current clamp procedures the voltage dependence and kinetics of the tetrodotoxin sensitive Na+ current was fully characterized. Cultured cells were shown to generate action potentials under electrical stimulation, and they were capable of repetitive spike discharge under the influence of 4-aminopyridine. These results demonstrate that tissue cultures constitute an excellent system to study the intrinsical properties of vestibular afferent neurons.

Características morfológicas y electrofisiológicas de las neuronas del ganglio vestibular en cultivo / Morphologic and electrophysiologic characteristics of cultured vestibular ganglia neurons

Vestibular afferent neurons have been classified on the basis of their spontaneous activity as regular and irregular; this has been attributed to their synaptic input, but it remains to be defined the participation of some intrinsical properties of the afferent neurons in the determination of their discharge pattern. In this work, we have developed tissue cultures of the rat vestibular ganglia. Isolated cells were plated using poly-D-lysine or collagen as substrates and L-15 or Neurobasal as culture media. After 48 hrs cells in the four experimental conditions give forth neurites of variable longitude. By using antibodies against the neurofilaments 160 kDa the cell structure was studied. Monopolar (30.6), bipolar (63.9) and multipolar (5.5) cells were found. By using the voltage and current clamp procedures the voltage dependence and kinetics of the tetrodotoxin sensitive Na+ current was fully characterized. Cultured cells were shown to generate action potentials under electrical stimulation, and they were capable of repetitive spike discharge under the influence of 4-aminopyridine. These results demonstrate that tissue cultures constitute an excellent system to study the intrinsical properties of vestibular afferent neurons.