GABA synthesis in isolated vestibulary tissue of chick inner ear

Meza, Graciela; Cárabez, A.; Ruíz, Mariano

doi:10.1016/0006-8993(82)91238-0

Cited by 33 publications

(10 citation statements)

References 23 publications

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“…Because the basilar papilla lacks efferent innervation from the CNS, and the spontaneous and evoked discharge in the afferent fibers could be blocked by the GABA A receptor antagonist picrotoxin, these findings were interpreted as evidence that GABA serves as a transmitter at hair cellafferent contacts. Subsequent studies confirmed and extended these observations in frog (López and Meza, 1988), chick (Meza et al, 1982), rat, and guinea pig (López et al, 1990). Biochemical studies further demonstrated the presence of the GABA synthetic enzyme glutamic acid decarboxylase (GAD) in the labyrinth, even following 8th nerve section (Meza et al, 1982;López and Meza, 1988), and the depletion of GAD following hair cell degeneration (Meza et al, 1989).…”

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confidence: 71%

“…GABA synthesis within hair cells was initially demonstrated in skate, toadfish, and frog (Flock and Lam, 1974) and was subsequently verified in frog (López and Meza, 1988), chick (Meza et al, 1982), guinea pig (López et al, 1990), and rat (López et al, 1990). GABA was localized immunocytochemically in both type I and type II hair cells by using several different GABA antibodies in chick (Usami et al, 1987a), chicken (Usami et al, 1989;Matsubara et al, 1995), pigeon (Matsubara et al, 1995), and guinea pig (López et al, 1990; but see Didier et al, 1990, for nonconfirmatory data) but was not observed in hair cells of the squirrel monkey (Usami et al, 1987b;Matsubara et al, 1995).…”

Section: Discussionmentioning

confidence: 98%

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γ‐Aminobutyric acid is present in a spatially discrete subpopulation of hair cells in the crista ampullaris of the toadfish Opsanus tau

Martinelli

Henderson

Friedrich

et al. 2004

J of Comparative Neurology

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Although gamma-aminobutyric acid (GABA) and glutamate are known to be present in the vestibular sensory epithelia of a variety of species, the functional relationship between these two transmitters is not clear. The present study addresses the three-dimensional spatial distribution of GABA and glutamate immunoreactivity in the vestibular labyrinth of the oyster toadfish by using whole end organs labeled by immunofluorescence with monoclonal anti-GABA and/or antiglutamate antibodies and visualized as whole mounts by multiphoton confocal microscopy. We find glutamate-immunoreactive hair cells present throughout the sensory epithelium. In contrast, prominent GABA immunoreactivity is restricted to a small population of hair cells located in the central region of the crista. Double immunofluorescence reveals two distinct staining patterns in GABA-labeled hair cells. Most ( approximately 80%) GABA-labeled cells show trace levels of glutamate, appropriate for the metabolic/synthetic role of cytoplasmic glutamate. The remainder of the GABA-stained cells contain substantial levels of both GABA and glutamate, suggesting transmitter colocalization. In the toadfish utricle, glutamatergic hair cells are present throughout the macula. GABA-immunoreactive hair cells follow the arc of the striola, and most GABA-labeled receptor cells coexpress glutamate. The localization of GABA was explored in other species as well. In the pigeon, GABAergic hair cells are present throughout the crista ampullaris. Our findings demonstrate that multiple, neurochemically distinct types of hair cells are present in vestibular sensory epithelia. These observations, together with the excitatory activity generally associated with 8th nerve afferent fibers, strongly suggest that GABA serves an important, specific, and complex role in determining primary afferent response dynamics.

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confidence: 71%

Section: Discussionmentioning

confidence: 98%

γ‐Aminobutyric acid is present in a spatially discrete subpopulation of hair cells in the crista ampullaris of the toadfish Opsanus tau

Martinelli

Henderson

Friedrich

et al. 2004

J of Comparative Neurology

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“…Supporting this idea the authors also found that picrotoxin blocked both resting and evoked activity in the nerve fibers of the crista ampullaris of the skate. Lately it has also been shown that chick vestibular sensory epithelium is capable of synthesizing GABA (Meza 1984;Meza et al 1982). On the other hand, Fex and Wenthold's studies (1976) revealed very low glutamic acid decarboxylase (GAD) activity in the inner and outer hair cells of the cochlea.…”

Section: Y-aminobutyric Acidmentioning

confidence: 97%

Synaptic Transmission in the Mechano- and Electroreceptors of the Acousticolateral System

Akoev

Andrianov

1989

Progress in Sensory Physiology 9

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“…The blocking of this conversion by aminoxyacetic acid (AOOAA), a well-known, in vitro GAD inhibitor, was an indisputable demonstration of GAD mediated GABA synthesis in the chick vestibule and of glutamate being its precursor [13].…”

Section: Criteria Concerning Gabamentioning

confidence: 99%

“…In the vestibule of a warm-blooded animal my laboratory was the first one to report that glutamate gives rise to GABA, since this amino acid was isolated from chick vestibular cristae when either uniformly-labeled glutamate (U-14 C glutamate) or 1-14 C glutamate were used as precursors [13]. The blocking of this conversion by aminoxyacetic acid (AOOAA), a well-known, in vitro GAD inhibitor, was an indisputable demonstration of GAD mediated GABA synthesis in the chick vestibule and of glutamate being its precursor [13].…”

Section: Criteria Concerning Gabamentioning

confidence: 99%

Modalities of GABA and Glutamate Neurotransmission in the Vertebrate Inner Ear Vestibule

Meza

2008

Neurochem Res

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GABA and glutamate have been postulated as afferent neurotransmitters at the sensory periphery inner ear vestibule in vertebrates. GABA has fulfilled the main criteria to act as afferent neurotransmitter but may also be a putative efferent neurotransmitter, mainly due to cellular localization of its synthesizing enzyme glutamate decarboxylase derived from biochemical, immunocytochemical, in situ hybridization and molecular biological techniques, whereas glutamate afferent neurotransmission role is supported mainly by pharmacological evidences. GABA and Glu could also act as afferent co-neurotransmitters based upon immunocytochemical techniques. This multiplicity was not considered earlier and postulates a peripheral modulation of afferent information being sent to higher vestibular centers. In order to make a definitive cellular assignation to these putative neurotransmitters it is necessary to have evidences derived from immunocytochemical and pharmacological experiments in which both substances are tested simultaneously.

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GABA synthesis in isolated vestibulary tissue of chick inner ear

Cited by 33 publications

References 23 publications

γ‐Aminobutyric acid is present in a spatially discrete subpopulation of hair cells in the crista ampullaris of the toadfish Opsanus tau

γ‐Aminobutyric acid is present in a spatially discrete subpopulation of hair cells in the crista ampullaris of the toadfish Opsanus tau

Synaptic Transmission in the Mechano- and Electroreceptors of the Acousticolateral System

Modalities of GABA and Glutamate Neurotransmission in the Vertebrate Inner Ear Vestibule

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