Synaptic effects elicited in the Retzius cells of the leech Hirudo medicinalis by stimulation of the segmental roots.
Research article published in Archives italiennes de biologie (1985)
Abstract
Electrical stimulation of the segmental roots of each ganglion of Hirudo medicinalis, elicits in both Retzius' cells inhibitory and excitatory effects. The IPSP and EPSP are chemical in nature, being dependent on the membrane potential, and suppressed by high Mg++. Selective inactivation of one RC shows that the responses of the contralateral RC are not due to electrotonic coupling between the two cells, but to synaptic actions impinging upon the membrane of both RCs. The two synaptic potentials appear to be mediated by two set of fibres with a different threshold to electrical stimulation. Their actions on the RCs appear to be polysynaptic on the basis of central latency. Simultaneous stimulation of two roots shows evidence for occlusion for IPSP and summation for EPSP, confirming the polysynaptic nature of the effects. The possible functional significance of the inhibitory and 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 segmental roots of each ganglion of Hirudo medicinalis, elicits in both Retzius' cells inhibitory and excitatory effects. The IPSP and EPSP are chemical in nature, being dependent on the membrane potential, and suppressed by high Mg++.
Por qué esto importa para la hirudoterapia
This experimental study examined the neurophysiology of the leech Hirudo medicinalis by electrically stimulating segmental roots and characterizing the resulting inhibitory and excitatory synaptic effects on Retzius cells. The findings demonstrated that these chemical synaptic responses are polysynaptic, membrane-potential dependent, suppressible by high Mg++, and mediated by fibers with different stimulation thresholds. Because the study investigates Hirudo medicinalis—the primary species used in hirudotherapy—it contributes to foundational knowledge of this organism's nervous system. However, its practical relevance to clinical practice or the leech secretome is absent, as the work is strictly basic neuroscience with no examination of therapeutic applications.
Citación
Synaptic effects elicited in the Retzius cells of the leech Hirudo medicinalis by stimulation of the segmental roots.
Carretta et al. · Archives italiennes de biologie, 1985
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Añadido a la biblioteca ASH: May 28, 2026 · Última actualización del sitio: June 18, 2026