In vivo stimulus-induced vasodilation occurs without IP3 receptor activation and may precede astrocytic calcium increase.
J Neurosci
; 33(19): 8411-22, 2013 May 08.
Article
em En
| MEDLINE
| ID: mdl-23658179
ABSTRACT
Calcium-dependent release of vasoactive gliotransmitters is widely assumed to trigger vasodilation associated with rapid increases in neuronal activity. Inconsistent with this hypothesis, intact stimulus-induced vasodilation was observed in inositol 1,4,5-triphosphate (IP3) type-2 receptor (R2) knock-out (KO) mice, in which the primary mechanism of astrocytic calcium increase-the release of calcium from intracellular stores following activation of an IP3-dependent pathway-is lacking. Further, our results in wild-type (WT) mice indicate that in vivo onset of astrocytic calcium increase in response to sensory stimulus could be considerably delayed relative to the simultaneously measured onset of arteriolar dilation. Delayed calcium increases in WT mice were observed in both astrocytic cell bodies and perivascular endfeet. Thus, astrocytes may not play a role in the initiation of blood flow response, at least not via calcium-dependent mechanisms. Moreover, an increase in astrocytic intracellular calcium was not required for normal vasodilation in the IP3R2-KO animals.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vasodilatação
/
Astrócitos
/
Cálcio
/
Receptores de Inositol 1,4,5-Trifosfato
Limite:
Animals
Idioma:
En
Revista:
J Neurosci
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Estados Unidos