Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
Date (from‐to) : 1994 -1995
Author : SATO Akio; UCHIDA Sae; SUZUKI Harue; HOTTA Harumi
1.We have developed a new system to continuously measure regional blood flow (rCBF) in the cortex of a conscious rat using laser Doppler flowmetry.Under anesthesia, the animal's skull was opened making a small square hole and a transparent acrylic plate was placed over the hole.A polyethylene cannula was fixed on the plate as a guide for the laser Doppler flowmeter (LDF) probe.Both the plate and guide cannula were fixed to the skull by dental cement.After recovery of anesthesia, the conscious animal was placed in a hammock with their legs firmly touching the floor.This system is recommended for the continuous measurement of rCBF in a conscious animal.
Using this method, rCBF in conscious rats was continuously measured during walking.rCBF in the frontal, parietal, and occipital corticies increased during walking at a mild speed (4cm/s) for a period of 30 s.The responses of rCBF in the three corticies were almost identical.Walking-induced increase in cortical rCBF was partially reduced by systemic administration of both blood brain barrior (BBB) -permeable muscarinic and nicotinic cholinergic receptor antagonists, but was unaffected by BBB-impermeable drugs.This suggests the involvement of both muscarinic and nicotinic receptors in the rCBF responses in the central nervous system.We could also demonstrate that extracellular acetylcholine in the cerebral cortex increased during walking at a mild speed in conscious rats.Circumstantially, these data suggest that the walking-induced increase in cortical rCBF is, at least in part, to activation of the cholinergic vasodilative system in the cortex originating in the nucleus basalis of Meynert.