Regional Blood-Brain Barrier Responses to Central Cholinergic Activity
Abstract
Time-dependent cerebrovascular responses to a seizure induced by the non-cholinergic convulsant, pentylenetetrazole (PTZ, 50 mg/kg), were examined in terms of regional cerebral blood flow (rCBF), regional cerebrovascular permeability-surface area products (rPS) for sucrose, and brain vascular space (BVS), as well as in terms of several peripheral cardiovascular parameters, including cardiac output and blood gases. Cerebrovascular measurements in 16 brain regions were performed at 1 hr, 15-18 hr and 1 week post-seizure, and were carried out in unanesthetized, unrestrained male Sprague-Dawley rats. Mean arterial blood pressure was elevated at 4 min (37%) and 12 min (13%) after seizure onset, returning to baseline levels by 2 hours. Thereafter, the blood gas pattern was normal. Cardiac outputs were unaffected in all post-seizure groups. BVS declined in most brain regions by an average of 5% within 1 hr post- seizure, significantly in the cerebellum (-18%). In contrast, by 15-18 hr post- seizure, BVS was elevated in 14 of 16 brain regions by an average of 10%, significantly in the olfactory bulb (+29%). Detailed histological examination failed to demonstrate delayed neuronal or axonal degeneration in any brain region at any time period. The data show that unique, acute and lingering regional changes in cerebrovascular physiology follow a single convulsive exposure to PTZ and suggest that disturbances in brain physiology may persist for relatively long times even in the absence of neuropathology.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 30, 1989
- Accession Number
- ADA216885
Entities
People
- Harold Goldman
- Robert F. Berman
Organizations
- Wayne State University