Postactivation inhibition of spontaneously active neurosecretory neurons in the medicinal leech.
Research article published in Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology (2007)
Abstract
Spontaneously active neurosecretory neurons in vertebrate and invertebrate nervous systems share similarities in firing frequencies, spike shapes, inhibition by the transmitters they themselves release and postactivation inhibition, an intensity-dependent period of suppressed spontaneous generation of action potentials following phases of high-frequency activity. High-frequency activation of spontaneously active serotonin-containing Retzius cells in isolated ganglia of the leech Hirudo medicinalis induced prolonged membrane hyperpolarisations causing periods of postactivation inhibition of up to 33 s. The duration of the inhibitory periods was directly related to both the number and rate of spikes during activation and was inversely proportional to a cell's spontaneous firing frequency. The periods of postactivation inhibition remained unaffected by both serotonin depletion through repeated injections of 5,7-dihydroxytryptamine and suppressing the afterhyperpolarisation following each action potential with tetraethylammonium (TEA), iberiotoxin or charybdotoxin, suggesting that neither autoinhibition by synaptic release of serotonin nor calcium-activated potassium channels contribute to the underlying mechanism. In contrast, the postactivation inhibitory period was significantly affected both by differential electrical stimulation of the same Retzius cells via microelectrodes filled with molar concentrations of either Na(+)-acetate or K(+)-acetate, and by partial inhibition of Na(+)/K(+)-ATPase with ouabain. Thus, postactivation inhibition in Retzius cells results from prolonged hyperpolarising activity of Na(+)/K(+)-ATPase stimulated by the accumulation of cytosolic Na(+ )during phases of high-frequency spike activity.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
Postactivation inhibition of spontaneously active neurosecretory neurons in the medicinal leech.
Por qué esto importa para la hirudoterapia
Este estudio examinó la inhibición postactivación en neuronas neurosecretoras espontáneamente activas, específicamente las células de Retzius que contienen serotonina en ganglios aislados de la sanguijuela medicinal, Hirudo medicinalis. Los investigadores investigaron los mecanismos que causan la hiperpolarización prolongada de la membrana tras la activación de alta frecuencia, encontrando que está impulsada por la actividad de la Na+/K+-ATPasa en lugar de por los canales de potasio activados por calcio o la autoinhibición por serotonina. Esta investigación es relevante para ASH, ya que explora la neurofisiología fundamental de la especie principal de sanguijuela utilizada en hirudoterapia. Sin embargo, el alcance se limita estrictamente a la neurociencia básica de invertebrados utilizando técnicas in vitro, sin aportar información sobre el secretoma de la sanguijuela, las propiedades anticoagulantes ni las aplicaciones clínicas de la hirudoterapia.
Citación
Postactivation inhibition of spontaneously active neurosecretory neurons in the medicinal leech.
Gocht et al. · Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology, 2007
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Añadido a la biblioteca ASH: May 28, 2026 · Última actualización del sitio: 18 de junio de 2026