[The role of stimulation of the medullary reticular formation on intracranial pressure in cold injured brain].
This study was carried out to study the effect of stimulation of the reticular formation of the medulla oblongata on intracranial pressure (ICP) and cerebral blood volume (CBV) in injured brain with increased ICP. CBV was measured by the photoelectric method from the parietal lobe. Seventeen hours prior to the experiments, cold induced edema was produced to increase basal ICP. In 15 cats, electric stimulation produced temporary increases in BP, ICP and CBV and progressive intracranial hypertension was never observed (Group A). In 9 animals, progressive increases in CBV and ICP up to 50 to 100 mmHg were evoked after cessation of stimulation (Group B). Prestimulation ICP in Group B was significantly higher than that of Group A. Rapid and simultaneous increases in ICP and CBV following stimulation strongly suggested that global increments of CBV secondary to loss of cerebral vasomotor tonus were responsible for producing progressive intracranial hypertension. In Group B, the stimulation electrodes were invariably located at the area of the nucleus reticularis parvocellularis and gigantocellularis. Our experimental results show that in increased ICP a stimulated or irritable condition of the medullary reticular formation will cause acute progressive intracranial hypertension.
Nagao
S
S
Department of Neurological Surgery, Kagawa Medical School.
Kawauchi
M
M
Tanimoto
N
N
Kuyama
H
H
Nishimoto
A
A
D000818:Animals; D001794:Blood Pressure; D001810:Blood Volume; D001929:Brain Edema / Q000209:etiology / Q000503:physiopathology; D001930:Brain Injuries / Q000209:etiology / Q000503:physiopathology*; D002415:Cats; D002560:Cerebrovascular Circulation; D003080:Cold Temperature / Q000009:adverse effects*; D004558:Electric Stimulation; D007427:Intracranial Pressure; D008526:Medulla Oblongata / Q000503:physiopathology*; D011559:Pseudotumor Cerebri / Q000209:etiology / Q000503:physiopathology; D012154:Reticular Formation / Q000503:physiopathology*