Effect of neurotropin on regional cerebral blood flow and systemic blood pressure

The effects of 30° head-down and head-up tilting on mean systemic blood pressure, carotid blood flow, and heart rate were studied in 16 dogs under morphine and Nembutal anesthesia. The tilting procedure was further repeated after denervation of the carotid sinus and aortic arch baroreceptors and after administration of a dihydrogenated ergot alkaloid mixture (Hydergine). The results indicate that the drop in pressure in the head-down position is primarily due to baroreceptor activity and that the baroreceptors are necessary for compensatory vasoconstriction on head-up tilting. Carotid blood flow decreased in both tilted positions in the control animals; the possible relationship to cerebral blood flow is discussed.

Download Full-text

Relations of blood pressure and head injury to regional cerebral blood flow

Journal of the Neurological Sciences ◽

10.1016/j.jns.2016.03.033 ◽

2016 ◽

Vol 365 ◽

pp. 9-14 ◽

Cited By ~ 2

Author(s):

Jason E. Kisser ◽

Allyssa J. Allen ◽

Leslie I. Katzel ◽

Carrington R. Wendell ◽

Eliot L. Siegel ◽

...

Keyword(s):

Blood Pressure ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Head Injury ◽

Regional Cerebral Blood Flow ◽

Regional Cerebral Blood

Download Full-text

Effect of hypoxia and hypercapnia on neurohypophyseal blood flow

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1986.250.1.h7 ◽

1986 ◽

Vol 250 (1) ◽

pp. H7-H15

Author(s):

D. F. Hanley ◽

D. A. Wilson ◽

R. J. Traystman

Keyword(s):

Blood Pressure ◽

Carbon Monoxide ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Regional Cerebral Blood Flow ◽

Brain Regions ◽

Regulatory Mechanisms ◽

Similar Increase ◽

Regional Cerebral Blood ◽

Pressure Controlled

Neurohypophyseal blood flow responses to hypoxia and hypercapnia were studied in pentobarbital anesthetized, paralyzed dogs. Arterial O2 content was lowered from control (18 +/- 2 vol%) to 8 +/- 1 vol% by either decreasing O2 tension (hypoxic hypoxia, HH) or by increasing carboxyhemoglobin saturation (carbon monoxide hypoxia, COH) at normal O2 tension. In all animals HH and COH resulted in similar increases in total cerebral blood flow (239 and 300%, respectively). Regional cerebral blood flow showed a similar increase for all brain regions except the neurohypophysis (NH). The NH increased its blood flow with HH (approximately 320% of control) but was unchanged with COH (117% of control). The responsiveness of NH blood vessels was tested under conditions of hypercapnia (10% CO2) and HH with blood pressure controlled by concurrent hemorrhage. The response of NH vessels to altered arterial O2 tension occurs independently of blood pressure. Systemic [H+] or CO2 tension produce only small changes in NH blood flow. These data suggest that hypoxic and hypercapnic regulatory mechanisms for the NH are different from those of other brain regions. The precise mechanism by which the NH hypoxic response occurs remains unclear, but our data suggest an important role for systemic arterial O2 tension and chemoreceptors.

Download Full-text