Effects of norepinephrine and ß2 receptor antagonist ICI 118,551 on whisker hair follicle mechanoreceptors dissatisfy Merkel discs being adrenergic synapses.
Mol Brain
; 12(1): 31, 2019 04 03.
Article
en En
| MEDLINE
| ID: mdl-30943999
ABSTRACT
Merkel discs, located in skin touch domes and whisker hair follicles, are tactile end organs essential for environmental exploration, social interaction, and tactile discrimination. Recent studies from our group and two others have shown that mechanical stimulation excites Merkel cells via Piezo2 channel activation to subsequently activate sensory neural pathways. We have further shown that mechanical stimulation leads to the release of 5-HT from Merkel cells to synaptically transmit tactile signals to whisker afferent nerves. However, a more recent study using skin touch domes has raised the possibility that Merkel discs are adrenergic synapses. It was proposed that norepinephrine is released from Merkel cells upon mechanical stimulation to subsequently activate ß2 adrenergic receptors on Merkel disc nerve endings leading to nerve impulses. In the present study, we examined effects of norepinephrine and ß2 adrenergic receptor antagonist ICI 118,551 on Merkel disc mechanoreceptors in mouse whisker hair follicles. We show that norepinephrine did not directly induce impulses from Merkel disc mechanoreceptors. Furthermore, we found that ICI 118,551 at 50 µM inhibited voltage-gated Na+ channels and suppressed impulses of Merkel disc mechanoreceptors, but ICI 118,551 at 1 µM had no effects on the impulse. These findings challenge the hypothesis of Merkel discs being adrenergic synapses.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Propanolaminas
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Sinapsis
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Norepinefrina
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Vibrisas
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Antagonistas Adrenérgicos beta
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Células de Merkel
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Folículo Piloso
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Mecanorreceptores
Límite:
Animals
Idioma:
En
Revista:
Mol Brain
Asunto de la revista:
BIOLOGIA MOLECULAR
/
CEREBRO
Año:
2019
Tipo del documento:
Article
País de afiliación:
Estados Unidos