Article date: 1991/6/24
PubMed ID: 1881625
Journal name: Neuroscience letters (ISSN: 0304-3940)
We used autoradiography to examine the extent of reversible inactivation produced by microinjection of lidocaine (40 micrograms/microliters saline) and muscimol (1 microgram/microliter saline). We measured intracortical spread of tracer amounts of labelled drug and local changes in uptake of [1-14C]glucose produced by the microinjection. The maximal average radii of regions of drug spread were 1.7 mm for both [14C]lidocaine and [3H]muscimol and were achieved within the first 20 min postinjection. The width of lidocaine injections decreased at longer postinjection times (30-60 min) but the width of muscimol injections remained relatively constant (30-120 min). Lidocaine radioactivity decreased faster from the injection site than muscimol radioactivity. Glucose autoradiograms showed a discrete region of maximally reduced glucose uptake (1.4 mm for lidocaine and 1.0 mm for muscimol) surrounded by a region of less reduced glucose uptake (up to approximately 3 mm). These findings suggest that, in the cortex, the effects of focal inactivation extend beyond the region of drug spread. Diffuse effects may be mediated of disfacilitation of cortico-cortical circuits.
Author List: Martin J H
Publication Types: Journal Article; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Muscimol; Lidocaine; Glucose;
Mesh terms: Animals; Autoradiography; Cerebral Cortex/metabolism; Female; Glucose/metabolism; Lidocaine/administration & dosage; Male; Microinjections; Muscimol/administration & dosage; Rats; Tissue Distribution;