Slow adaptation in spider mechanoreceptor neurons.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol
; 191(5): 403-11, 2005 May.
Article
em En
| MEDLINE
| ID: mdl-15750818
ABSTRACT
Slow adaptation of action potential firing is a common but poorly understood property of sensory neurons. We quantified slow adaptation in a cuticular mechanoreceptor organ of the spider, Cupiennius salei, by stimulating with continuous pseudorandom mechanical displacements while recording action potentials intracellularly from the cell bodies. Firing rate declined over a period of several minutes before reaching a steady level at about half the initial rate. This slow adaptation was fitted by an exponential decay with mean time constant of 18.5 s. Recovery from slow adaptation was also fitted by an exponential process, but with a longer time constant of 167 s. The receptor potential produced by the same stimulation protocol did not change its amplitude or dynamics, showing that slow adaptation occurs during action potential encoding from the receptor potential. Experiments with chemical blockers of calcium entry or the known potassium currents failed to reduce the slow adaptation. The Na+/K+ pump blocker Ouabain decreased the time constant of slow adaptation, suggesting that ion accumulation is involved. In some experiments, a second class of small action potentials were observed, which were tentatively attributed to failed conduction from the sensory dendrite through the soma to the axon.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Aranhas
/
Aclimatação
/
Mecanorreceptores
/
Neurônios
Limite:
Animals
Idioma:
En
Revista:
J Comp Physiol A Neuroethol Sens Neural Behav Physiol
Assunto da revista:
CIENCIAS DO COMPORTAMENTO
/
FISIOLOGIA
/
NEUROLOGIA
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Canadá