TY - JOUR
T1 - Acute downregulation of Cx43 alters P2Y receptor expression levels in mouse spinal cord astrocytes
AU - Suadicani, Sylvia O.
AU - De Pina-Benabou, Mara Helena
AU - Urban-Maldonado, Marcia
AU - Spray, David C.
AU - Scemes, Eliana
PY - 2003/4/15
Y1 - 2003/4/15
N2 - Propagation of intercellular calcium waves (ICW) between astrocytes depends on the diffusion of signaling molecules through gap junction channels and diffusion through the extracellular space of neuroactive substances acting on plasmalemmal receptors. The relative contributions of these two pathways vary in different brain regions and under certain pathological conditions. We have previously shown that in wild-type spinal cord astrocytes, ICW are primarily gap junction-dependent, but that deletion of the main gap junction protein (Cx43) by homologous recombination results in a switch in mode of ICW propagation to a purinoceptor-dependent mechanism. Such a compensatory mechanism for ICW propagation was related to changes in the pharmacological profile of P2Y receptors, from an adenine-sensitive P2Y1, in wild-type, to a uridine-sensitive P2U receptor subtype, in Cx43 knockout (KO) astrocytes. Using oligonucleotide antisense to Cx43 mRNA for acute downregulation of connexin43 expression levels, we provide evidence for the molecular nature of such compensatory mechanism. Pharmacological studies and Western blot analysis indicate that there is a reciprocal regulation of P2Y1 and P2Y4 expression levels, such that downregulation of Cx43 leads to decreased expression of the adenine-sensitive P2Y1 receptor and increased expression of the uridine-sensitive P2Y4 receptor. This change in functional expression of the P2Y receptor subtype population in acutely downregulated Cx43 was paralleled by changes in the mode of ICW propagation, similar to that previously observed for Cx43 KO spinal cord astrocytes. On the basis of these results, we propose that Cx43 regulates both modes of ICW by altering P2Y receptor subtype expression in addition to providing intercellular coupling.
AB - Propagation of intercellular calcium waves (ICW) between astrocytes depends on the diffusion of signaling molecules through gap junction channels and diffusion through the extracellular space of neuroactive substances acting on plasmalemmal receptors. The relative contributions of these two pathways vary in different brain regions and under certain pathological conditions. We have previously shown that in wild-type spinal cord astrocytes, ICW are primarily gap junction-dependent, but that deletion of the main gap junction protein (Cx43) by homologous recombination results in a switch in mode of ICW propagation to a purinoceptor-dependent mechanism. Such a compensatory mechanism for ICW propagation was related to changes in the pharmacological profile of P2Y receptors, from an adenine-sensitive P2Y1, in wild-type, to a uridine-sensitive P2U receptor subtype, in Cx43 knockout (KO) astrocytes. Using oligonucleotide antisense to Cx43 mRNA for acute downregulation of connexin43 expression levels, we provide evidence for the molecular nature of such compensatory mechanism. Pharmacological studies and Western blot analysis indicate that there is a reciprocal regulation of P2Y1 and P2Y4 expression levels, such that downregulation of Cx43 leads to decreased expression of the adenine-sensitive P2Y1 receptor and increased expression of the uridine-sensitive P2Y4 receptor. This change in functional expression of the P2Y receptor subtype population in acutely downregulated Cx43 was paralleled by changes in the mode of ICW propagation, similar to that previously observed for Cx43 KO spinal cord astrocytes. On the basis of these results, we propose that Cx43 regulates both modes of ICW by altering P2Y receptor subtype expression in addition to providing intercellular coupling.
KW - Antisense oligonucleotides
KW - Calcium waves
KW - Dye coupling
KW - Electrical coupling
KW - Gap junction
KW - Purinoceptor
UR - http://www.scopus.com/inward/record.url?scp=0038666131&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0038666131&partnerID=8YFLogxK
U2 - 10.1002/glia.10197
DO - 10.1002/glia.10197
M3 - Article
C2 - 12655600
AN - SCOPUS:0038666131
SN - 0894-1491
VL - 42
SP - 160
EP - 171
JO - Glia
JF - Glia
IS - 2
ER -