Development of GAD-immunoreactivity in the dorsal cochlear nucleus of the hamster and cat

light and electron microscopic observations

Laura Schweitzer, Tina Cecil, Edward J. Walsh

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Physiologic and pharmacologie evidence suggests that inhibitory influences are active in the mammalian dorsal cochlear nucleus (DCN) by the onset of hearing, while anatomical evidence suggests that inhibitory synapses are not present until days or weeks later. One inhibitory neurotransmitter in the DCN is gamma aminobutyric acid (GABA) and its presence can be indexed by immunohistochemical localization of its synthetic enzyme glutamic acid decarboxylase (GAD). The present study investigated the ingrowth and synapse formation of GAD-immunoreactive inputs in the DCN of cat and hamster. GAD-immunoreactive puncta are present in the DCN of the cat at birth and of the hamster on postnatal day (PND) 3. Thus, the present data correlate well with the physiologic and pharmacologie evidence. In both species the first labelled puncta are near the dorsal acoustic stria and may originate from efferent axons in the stria. Several days later a band of labelled puncta is found in the fusiform cell layer. This location is equivalent to the termination zone of cartwheel cells, GAD- immunoreactive interneurons in the DCN. Based on this spatiotemporal sequence in the appearance of GAD-immunoreactive puncta, we suggest that sources of GABA extrinsic to the DCN mature first, followed by intrinsic sources.

Original languageEnglish (US)
Pages (from-to)240-252
Number of pages13
JournalHearing Research
Volume65
Issue number1-2
DOIs
StatePublished - Jan 1 1993

Fingerprint

Cochlear Nucleus
Glutamate Decarboxylase
Cricetinae
Cats
Electrons
Light
Synapses
gamma-Aminobutyric Acid
Interneurons
Hearing
Neurotransmitter Agents
Axons
Parturition
Enzymes

Keywords

  • Auditory
  • Cochlear nucleus
  • Development
  • GABA
  • Glutamic acid decarboxylase

ASJC Scopus subject areas

  • Sensory Systems

Cite this

Development of GAD-immunoreactivity in the dorsal cochlear nucleus of the hamster and cat : light and electron microscopic observations. / Schweitzer, Laura; Cecil, Tina; Walsh, Edward J.

In: Hearing Research, Vol. 65, No. 1-2, 01.01.1993, p. 240-252.

Research output: Contribution to journalArticle

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