The electric lobes of the electric ray (Torpedo marmorata) are innervated by GABAergic fibres: immunocytochemical evidence for dual innervation of electromotoneurons.

Document Type

Article

Abstract

It is currently thought that the electric lobes of electric rays are innervated by a single neuronal system, the oval nucleus system. In the work reported here, the innervation of the electric lobes was studied with silver staining methods, acetylcholinesterase histochemistry and gamma-aminobutyric acid (GABA) immunocytochemistry. Two types of axon were observed in the lobes: thick GABA-immunonegative fibres, which originated from the oval nucleus, and thin GABAergic fibres of unknown origin, here reported for the first time. Electromotoneurons were strongly acetylcholinesterase-positive. Non-GABAergic and non-cholinergic neurons were observed in the oval nucleus, which is innervated by GABA-immunoreactive fibres. These results suggest that GABA may modulate electric discharge both directly, by GABAergic fibres that project to the lobes, and indirectly, by GABAergic fibres that project to the oval nucleus.

Keywords

Acetylcholinesterase, Animals, Electric Organ, Immunohistochemistry, In Vitro Techniques, Motor Neurons, Nerve Fibers, Neurotransmitter Agents, Torpedo, gamma-Aminobutyric Acid

Medical Subject Headings

Acetylcholinesterase; Animals; Electric Organ; Immunohistochemistry; In Vitro Techniques; Motor Neurons; Nerve Fibers; Neurotransmitter Agents; Torpedo; gamma-Aminobutyric Acid

Publication Date

12-8-1995

Publication Title

Neuroscience letters

ISSN

0304-3940

Volume

201

Issue

2

First Page

171

Last Page

174

PubMed ID

8848245

Digital Object Identifier (DOI)

10.1016/0304-3940(95)12163-3

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