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Updated: Jun 27, 2026

Intracellular Recording, Sensory Field Mapping, and Culturing Identified Neurons in the Leech, Hirudo medicinalis
Published on: November 4, 2013
Calcium spikes in a leech nonspiking neuron
Lorena Rela1, Sung Min Yang, Lidia Szczupak
1Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IFIBYNE-CONICET, LFBM, Ciudad Universitaria, Pabellón II, piso 2, 1428, Buenos Aires, Argentina.
Nonspiking (NS) neurons in leeches generate graded, spike-like events crucial for motor control. These events depend on calcium and potassium conductances, aiding signal transmission in their extensive neurites.
Area of Science:
- Neuroscience
- Electrophysiology
- Leech Nervous System
Background:
- Nonspiking (NS) neurons in the leech nervous system have extensive arborizations and regulate motoneuron coactivation.
- The electrophysiological properties of NS neurons were investigated to understand signal transmission along their neurites.
Purpose of the Study:
- To investigate the electrophysiological properties of leech NS neurons.
- To determine if voltage-dependent conductances aid signal transmission in extensive neurites.
Main Methods:
- Electrophysiological recordings from leech NS neurons.
- Stimulation with varying electrical intensity and duration.
- Manipulation of extracellular Ca2+ and Na+ concentrations.
- Intracellular application of tetraethylammonium (TEA).
Main Results:
- NS neurons exhibited graded, spike-like responses dependent on stimulus intensity and duration, not all-or-none.
- Responses were activated around -50 mV, with amplitude dependent on extracellular Ca2+.
- Responses were unaffected by Na+ concentration changes but prolonged by TEA.
Conclusions:
- NS neurons possess voltage-dependent low-threshold Ca2+ and TEA-sensitive K+ conductances.
- These conductances likely contribute to shaping synaptic signals and signal transmission along extensive neurites.
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