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 language | English (US) |
|---|---|
| Pages (from-to) | 240-252 |
| Number of pages | 13 |
| Journal | Hearing Research |
| Volume | 65 |
| Issue number | 1-2 |
| DOIs | |
| State | Published - Jan 1 1993 |
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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 journal › Article
}
TY - JOUR
T1 - Development of GAD-immunoreactivity in the dorsal cochlear nucleus of the hamster and cat
T2 - light and electron microscopic observations
AU - Schweitzer, Laura
AU - Cecil, Tina
AU - Walsh, Edward J.
PY - 1993/1/1
Y1 - 1993/1/1
N2 - 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.
AB - 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.
KW - Auditory
KW - Cochlear nucleus
KW - Development
KW - GABA
KW - Glutamic acid decarboxylase
UR - http://www.scopus.com/inward/record.url?scp=0027388985&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027388985&partnerID=8YFLogxK
U2 - 10.1016/0378-5955(93)90217-O
DO - 10.1016/0378-5955(93)90217-O
M3 - Article
VL - 65
SP - 240
EP - 252
JO - Hearing Research
JF - Hearing Research
SN - 0378-5955
IS - 1-2
ER -