Vasopressin increases [Ca(2+)](i) in differentiated astrocytes by activation of V1b/V3 receptors but has no effect in mature cortical neurons.
Vasopressin (AVP) plays an important role in regulation of astrocytic, but not neuronal, water content and cell volume during hydro-osmotic challenge. To investigate the intracellular mechanism(s) signaling this response, [Ca(2+)](i) was measured fluorometrically in cultured cerebrocortical astrocytes and neurons, obtained from neonatal and fetal mouse brains, and matured during the culturing period. In astrocytes, [Ca(2+)](i) increased with an EC(50) of between 10(-10) and 10(-9) M AVP, the maximum increase was approximately 100 nM, and the response was independent of extracellular Ca(2+), identifying the receptor as being of the V1b/V3 subtype. In contrast, AVP had no effect on [Ca(2+)](i) in cortical neurons. This cellular difference is consistent with the ability of AVP to increase water permeability in astrocytes but not in neurons.
Chen
Y
Y
Department of Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Zhao
Z
Z
Hertz
L
L
D000818:Animals; D000831:Animals, Newborn; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D016922:Cellular Senescence; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D004622:Embryo, Mammalian; D007425:Intracellular Membranes / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D009994:Osmolar Concentration; D017483:Receptors, Vasopressin / Q000187:drug effects / Q000502:physiology*
D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin; D002118:Calcium