Trigeminovascular fibers increase blood flow in cortical gray matter by axon reflex-like mechanisms during acute severe hypertension or seizures

Journal Article · Wed Feb 01 00:00:00 EST 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.4.1401· OSTI ID:5050255

Sakas, D E; Moskowitz, M A; Kano, M; Ogilvy, C S ^[1]; Wei, E P; Kontos, H A ^[2]

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1. Harvard Medical School, Boston, MA (USA)
2. Medical College of Virginia, Richmond (USA)

Cerebral blood flow was measured and compared in 10 symmetrical brain regions following unilateral trigeminal ganglionectomy, sham operation, or trigeminal root section (rhizotomy) in cats. Multiple determinations were obtained in anesthetized and paralyzed animals using radiolabeled microspheres during (i) normocapnia-normotension, (ii) hypercapnia, (iii) angiotensin-induced acute severe hypertension, or (iv) bicuculline-induced seizures. Flow was symmetrical in all brain regions at rest and during increases induced by hypercapnia in the three groups. During severe hypertension or seizures, marked elevations developed bilaterally. In ganglionectomized animals, increases due to hypertension or seizures were attenuated by 28-32% on the denervated side within cortical gray matter regions corresponding to the anterior, middle, and posterior cerebral arteries. Flow was symmetrical within all brain regions in sham-operated animals and in the rhizotomy group, despite comparable increases in regional cerebral blood flow induced by angiotensin. Hence, the trigeminal nerve mediates blood flow adaptations during severe hypertension and seizures. Furthermore, since trigeminal cell bodies and peripheral axons are destroyed or degenerate following ganglionectomy but not following rhizotomy, local axon reflex-like mechanisms mediate these increases in cerebral blood flow.

• OSTI ID: 5050255
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 86:4; ISSN 0027-8424
• Country of Publication: United States
• Language: English

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