RESUMO
Vascular control mechanisms have been studied extensively in mice. However, an in vitro characterization of penetrating intracerebral arterioles has not been reported. We describe methods for isolation and cannulation for mouse intracerebral arterioles. This technique allows analysis of mouse cerebral arteriolar physiology and pharmacology without the confounding influences of the surrounding brain elements. Penetrating intracerebral arterioles from adult C57/BL6 wild-type (WT) mice were isolated at 4 degrees C, transferred to an inverted microscope and cannulated at both ends using a dual glass micropipette system, wherein intraluminal flow (0.2 microl/min) and pressure (60 mmHg) were maintained. The arterioles developed spontaneous tone when the chamber was warmed to 37 degrees C, with the resulting diameter reaching 68.4+/-0.9% of passive diameter (29.8+/-1.1 microm). After the development of spontaneous tone, incremental changes in luminal pressure from 20 to 140 mmHg induced myogenic responses. Acidosis (pH 6.8) and alkalosis (pH 7.6) caused dilation (20.0+/-1.4%) and constriction (17.2+/-1.4%), respectively. Extraluminal adenosine (ADO (10 microM); 24.3+/-3.6%) and sodium nitroprusside (SNP (10 microM); 28.6+/-4.1%) and intraluminal adenosine 5'-triphosphate (ATP (10 microM); 20.0+/-3.9%) resulted in vasodilation similar in magnitude to that observed in rat arterioles. This information provides a foundation for elucidating cerebral vascular control mechanisms in genetically engineered mice.