Identification of carbonic anhydrase activity in bullfrog olfactory receptor neurons: histochemical localization and role in CO2 chemoreception.
J Comp Physiol A
; 182(2): 163-74, 1998 Feb.
Article
em En
| MEDLINE
| ID: mdl-9463917
ABSTRACT
The objectives of this study were to determine (1) the frequency and distribution of carbonic anhydrase (CA) activity in the bullfrog nasal cavities, and (2) whether inhibition of nasal CA affects the olfactory receptor response to CO2 or other odorants. It was found, using Hansson's staining technique, that some olfactory receptor neurons exhibited CA activity and that these CA-positive receptors were distributed throughout the nasal cavity with peak densities in the dorsal and ventral sensory epithelial regions. To test for the role of CA in olfactory transduction, electro-olfacto-grams (EOGs) were recorded from the surface of the ventral sensory epithelium in response to 2-s pulses of 5% CO2 and amyl acetate before and after topical CA inhibition with acetazolamide (10(-3) mol.l-1). In 52 bullfrogs, 1222 sites on the ventral epithelium were tested resulting in 23 locations that exhibited a response to 5% CO2. Inhibition of CA caused an immediate 65% reduction in the EOG response to CO2 while the response to amyl acetate was not affected. These results, along with the histochemical localization of CA in some olfactory receptor neurons, indicate that CA plays a role in the detection of CO2 in frog olfactory neurons and that only a small population of olfactory receptor neurons are CO2 sensitive.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Dióxido de Carbono
/
Células Quimiorreceptoras
/
Anidrases Carbônicas
/
Neurônios Receptores Olfatórios
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Comp Physiol A
Assunto da revista:
CIENCIAS DO COMPORTAMENTO
/
FISIOLOGIA
/
NEUROLOGIA
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Estados Unidos