The effects of noxious mechanical stimulation of various segmental areas on systemic blood pressure and heart rate in anesthetized rats with the spinal cord intact or transected at the cervical level

1994 ◽  
Vol 19 ◽  
pp. S216
Author(s):  
A. Kimura ◽  
H. Ohsawa ◽  
A. Sato ◽  
Y. Sato
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Heart Rate ◽  
Mechanical Stimulation ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Anesthetized Rats ◽  
Noxious Mechanical Stimulation ◽  
Cervical Level ◽  
Stimulation Of

The histopathology of experimental spinal cord trauma

1978 ◽  
Vol 48 (6) ◽  
pp. 1002-1007 ◽  
Author(s):  
Stephen E. Rawe ◽  
William A. Lee ◽  
Phanor L. Perot
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Systemic Blood Pressure ◽  
Post Injury ◽  
Systemic Blood ◽  
Edema Formation ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal ◽  
Marked Enhancement

✓ The early sequential histopathological alterations following a concussive paraplegic injury to the posterior thoracic spinal cord in cats were studied. The lack of significant progression of hemorrhages over a 4-hour period after injury indicates that most hemorrhages probably occur within the first hour. The marked enhancement or retardation of hemorrhages in the post-injury period, when the blood pressure was increased or decreased, respectively, demonstrates the loss of autoregulation of spinal cord vasculature at the trauma site after a concussive paraplegic injury. Progressive edema formation was evident over a 4-hour period following injury, and it could be enhanced or retarded by elevation or reduction of the systemic blood pressure.

scholarly journals Changes in Respiratory Rate, Blood Pressure and Heart Rate Variability in Rabbits during Orthostasis

2006 ◽  
Vol 75 (1) ◽  
pp. 3-12 ◽  
Author(s):  
J. Mokrý ◽  
T. Remeňová ◽  
K. Javorka
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Respiratory Rate ◽  
Supine Position ◽  
Spectral Power ◽  
Systemic Blood Pressure ◽  
Microcomputer System ◽  
Systemic Blood ◽  
Frequency Bands

The purpose of the study was to evaluate the changes of respiratory rate, systemic blood pressure and heart rate variability parameters (HRV) during orthostasis in anaesthetized rabbits. Furthermore, these changes were influenced by affecting the renin-angiotensin-aldosterone (RAA) system and autonomic nervous system (ANS) to study the mechanisms participating in activity of spectral frequency bands of HRV in rabbits. Ten adult rabbits (Chinchilla) were anaesthetized by ketamine and flunitrazepam. The systemic blood pressure, tidal volume and respiratory rate were measured. HRV was evaluated by microcomputer system VariaPulse TF3E. The R-R intervals were derived from the electrocardiogram signal from subcutaneous needle electrodes. The evaluation of HRV in very low (VLF; 0.01-0.05 Hz), low (LF; 0.05-0.15 Hz) and high frequency bands (HF; 0.15-2.0 Hz) was made and parameters of frequency and time analysis were calculated. The measurements were made in horizontal (supine) position, in orthostasis (the angle of 60 °) and again in supine position before and after enalapril (0.5 mg/kg b.w.), metipranolol (0.2 mg/kg b.w.), and after subsequent bilateral cervical vagotomy. The orthostasis in anaesthetized rabbits is accompanied by depression of respiratory rate reversed only by vagotomy. Furthermore, decrease of systemic blood pressure, unchanged heart rate and increased characteristics of heart rate variability were found, with predominant increase of spectral power in LF and VLF bands. This elevation can be eliminated only by complete blockade of ANS. Although the participation of ANS or RAA system in modification of individual HRV frequency bands is not as specific as in humans, we confirmed the participation of RAA system in determination of the VLF band.

Neural mechanism underlying basilar arterial constriction by intracisternal L-NNA in anesthetized dogs

1993 ◽  
Vol 265 (1) ◽  
pp. H103-H107 ◽  
Author(s):  
N. Toda ◽  
K. Ayajiki ◽  
T. Okamura
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cerebral Arteries ◽  
Neural Mechanism ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Anesthetized Dogs ◽  
Arterial Constriction ◽  
Synthase Inhibitor

Basilar arterial diameters were angiographically measured in anesthetized dogs in which systemic blood pressure and heart rate were also monitored. Injections of NG-nitro-L-arginine (L-NNA), a NO synthase inhibitor, into the cisterna magna produced a significant, persistent decrease in arterial diameter, the effect being reversed by intracisternal injections of L-arginine. The vasoconstrictor effect of L-NNA was diminished in dogs treated with hexamethonium. On the other hand, treatment with phentolamine in a dose sufficient to lower blood pressure to a level similar to that attained with hexamethonium did not inhibit, but rather potentiated, the effect of intracisternal L-NNA. Nicotine injected into the vertebral artery significantly dilated the basilar artery. The effect was abolished by treatment with L-NNA applied intracisternally, the inhibition being reversed by the addition of L-arginine. Systemic blood pressure and heart rate were not altered by intracisternally applied L-NNA and L-arginine. These findings support the hypothesis that basilar arterial constriction caused by intracisternal L-NNA is associated with a suppression of NO synthesis in nitroxidergic nerves innervating the cerebroarterial wall rather than an elimination of basal release of NO from the endothelium. Functional importance of nitroxidergic vasodilator innervation in cerebral arteries in vivo is thus clarified.

Responses of the canine myocardium to stimulation of thoracic cardiac nerves

1977 ◽  
Vol 232 (5) ◽  
pp. H485-H494 ◽  
Author(s):  
J. E. Norris ◽  
W. C. Randall
Keyword(s):  
Blood Pressure ◽  
Systemic Blood Pressure ◽  
Type Ii ◽  
Systemic Blood ◽  
Type Iv ◽  
The Right ◽  
Alpha Chloralose ◽  
Canine Myocardium ◽  
Cardiac Nerves ◽  
Stimulation Of

The thoracic cardiac nerves were stimulated in each of 21 dogs anesthetized with alpha chloralose. Recordings were made of heart rate, blood pressure, and contractile force from all four cardiac chambers. Walton-Brodie strain-gauge arches were sutured to both atria, and to three locations of each ventricle, representing both anterior and posterior surfaces. The functional autonomic components of each nerve were summarized and classified into four basic types. Types I and II were both located medial to the thoracic vagi. These were shown to contain both sympathetic and parasympathetic components traveling to all four chambers of the heart. The sympathetic componnent of the type II nerves produced reflex changes in force of contraction and systemic blood pressure. Nerves classified as types III and IV produced no parasympathetic effect on the heart. These were all located lateral to the thoracic vagi. While the type III nerves carried sympathetic efferent fibers to all four chambers, the type IV nerve carried sympathetic fibers predominantly to the right atrium.

Baroreceptor influence on postural changes in blood pressure and carotid blood flow

1963 ◽  
Vol 205 (2) ◽  
pp. 360-364 ◽  
Author(s):  
Francis L. Abel ◽  
John H. Pierce ◽  
Warren G. Guntheroth
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Sinus ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Carotid Blood Flow ◽  
Postural Changes ◽  
Nembutal Anesthesia

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.

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