Observation of the blood-brain barrier function and vasomotor response in rat microcirculation using intravital fluorescence microscopy.
The blood-brain barrier function and the vasomotor response in rat microcirculation was studied using a closed cranial window technique and an intravital fluorescence microscope with an attempt to reduce both the light intensity and the amount of 2% Na(+)-fluorescein to as little as possible. The light intensities in the focus were less than or equal to 2.5 mW/cm2, and with the low-light TV camera we were able to reduce the total amount of the dye to less than or equal to 0.7 ml during 6-h experiments. Observing the brain surface every 30 min showed that the barrier function remained intact for up to 6.0 h following the first iv administration of the dye. This study has reconfirmed that the pial vessels have physiological vasomotor responses (e.g., CO2 reactivity). The osmotic barrier disruption started at a small venule 10 min after the start of superfusion with mannitol (1000 mOsm/liter). In conclusion, the microscope system and the small animal model used in this study were useful in studying the blood-brain barrier function and the vasomotor response simultaneously under various experimental conditions.
Kawamura
S
S
Department of Surgical Neurology, Research Institute for Brain and Blood Vessels-AKITA, Japan.
Yasui
N
N
D000818:Animals; D001160:Arterioles / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D001812:Blood-Brain Barrier / Q000502:physiology*; D002248:Carbon Monoxide / Q000494:pharmacology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D008297:Male; D008833:Microcirculation / Q000166:cytology / Q000502:physiology*; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014699:Venules / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
D002248:Carbon Monoxide