Intracellular Recording, Sensory Field Mapping, and Culturing Identified Neurons in the Leech, <i>Hirudo medicinalis</i>

Abstract

The freshwater leech, Hirudo medicinalis, is a versatile model organism that has been used to address scientific questions in the fields of neurophysiology, neuroethology, and developmental biology. The goal of this report is to consolidate experimental techniques from the leech system into a single article that will be of use to physiologists with expertise in other nervous system preparations, or to biology students with little or no electrophysiology experience. We demonstrate how to dissect the leech for recording intracellularly from identified neural circuits in the ganglion. Next we show how individual cells of known function can be removed from the ganglion to be cultured in a Petri dish, and how to record from those neurons in culture. Then we demonstrate how to prepare a patch of innervated skin to be used for mapping sensory or motor fields. These leech preparations are still widely used to address basic electrical properties of neural networks, behavior, synaptogenesis, and development. They are also an appropriate training module for neuroscience or physiology teaching laboratories.

Mechanisms of electromagnetic influences and effects on membrane systems in neurons and cardiomyocytes

“…It enable us to use the neu rons of mollusks as eligible models [9][10][11][12][13][14][15][16][17][18], in paral lel with the neurons of warmblooded animals, for experimental research on the performance of the ion channels and the mechanisms of influences on them made by various physical factors, chemical substanc es and pharmaceutical drugs either of already known nature or being designed. Our studies were carried out on the large identified (100-200 µm) neurons of the parietal ganglia (LPaG and RPaG) ( Fig.…”

Ultrasound Stimulations Induce Prolonged Depolarization and Fast Action Potentials in Leech Neurons

“…This invertebrate model can generate a broad range of behaviors [25] , [26] , but possesses a simple nervous system that can be easily accessed to extract individual ganglia, the anatomical organization of which is highly conserved across specimens [27] . Neurons within a ganglion are functionally characterized and identifiable by their position, size, and electrophysiological profile [28] , [29] , and offer very reliable responses to EL stimulation. Finally, it is possible to record viable neural responses from an isolated ganglion for extended periods of time [29] .…”

“…Neurons within a ganglion are functionally characterized and identifiable by their position, size, and electrophysiological profile [28] , [29] , and offer very reliable responses to EL stimulation. Finally, it is possible to record viable neural responses from an isolated ganglion for extended periods of time [29] .…”

Brief Electrical Stimulation Triggers an Effective Regeneration of Leech CNS

“…Leeches were anesthetized on ice for 30 min before dissection and were pinned, dorsal side up, to a layer of Sylgard on the bottom of the dissection chamber. Dissection was made according to an established procedure (Titlow et al, 2013). Briefly, a longitudinal cut was made through skin and muscle layers along the dorsal midline of the leech to expose the nerve cord and segmental ganglia.…”