Two bidirectional nerve cord systems converging with electrical and chemical synapses on the Retzius cells of the leech Hirudo Medicinalis.
Research article published in Archives italiennes de biologie (1981)
Abstract
Electrical stimulation of the ventral cord of H. medicinalis elicits in both Retzius' cells of each segmental ganglion an EPSP which is composed by an early and a late component. The early EPSP is electrical in nature, since it is unaffected by displacements of the membrane potential and by high Mg2+, whereas the late one is chemical, being reversed in sign by membrane depolarization and suppressed by high Mg2+. Latency measurements show that the electrical and chemical EPSP components are mediated by two different pathways characterized by conduction velocities of 0.5 and 0.3 m/sec respectively. Both pathways run in each of the lateral connectives and propagate impulses in anterior and posterior direction. Collision experiments show that ascending and descending impulses along the pathway mediating the electrical EPSP travel along the same fibres. Separate stimulation of the lateral connectives and selective inactivation of one Retzius' cell show that both pathways converge onto each Retzius' cell show that both pathways converge onto each Retzius cell. The possible functional significance of the two excitatory pathways is discussed.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
Electrical stimulation of the ventral cord of H. medicinalis elicits in both Retzius' cells of each segmental ganglion an EPSP which is composed by an early and a late component.
Por qué esto importa para la hirudoterapia
Este estudio examinó la señalización neural en la sanguijuela Hirudo medicinalis, mostrando que la estimulación del cordón ventral evocó EPSPs en las células de Retzius con un componente eléctrico temprano y un componente químico tardío, mediados por vías con velocidades de conducción de aproximadamente 0,5 y 0,3 m/s, respectivamente. Ambas vías transcurrían por los conectivos laterales, se propagaban en sentido anterior y posterior, y convergían en cada célula de Retzius. El resumen versa sobre neurobiología fundamental de la sanguijuela y sobre su circuitería sináptica. No aborda la hirudoterapia, el secretoma de la sanguijuela, los mecanismos terapéuticos ni las aplicaciones clínicas, de modo que no aporta evidencia directa relevante para la terapia con sanguijuelas a pesar de involucrar a una especie de sanguijuela.
Citación
Two bidirectional nerve cord systems converging with electrical and chemical synapses on the Retzius cells of the leech Hirudo Medicinalis.
Carretta et al. · Archives italiennes de biologie, 1981
Contexto clínico relacionado
Explore cómo esta investigación se conecta con la práctica clínica
Añadido a la biblioteca ASH: May 28, 2026 · Última actualización del sitio: 18 de junio de 2026