Pressor responses and adrenomedullary catecholamine release during brain stimulation in the rat

1981 ◽  
Vol 59 (5) ◽  
pp. 485-492 ◽  
Author(s):  
Pierre Gauthier
Keyword(s):  
Blood Pressure ◽  
Electrical Stimulation ◽  
Brain Stimulation ◽  
Active Sites ◽  
Pressor Response ◽  
Secondary Phase ◽  
Plasma Catecholamine ◽  
Central Gray Matter ◽  
Central Gray ◽  
Stimulation Of

Electrical stimulation of the diencephalon and rostral mesencephalon produced a biphasic pressor response consisting of an initial sharp rise followed by a more prolonged elevation in blood pressure. Active sites from which comparable responses could be evoked were found in the ventral medial and lateral hypothalamus, in the region of the parafascicularis nucleus, and in the central gray matter and the tegmentum of the mesencephalon. Together with the biphasic pressor response brain stimulation also increased plasma catecholamine (CA) concentrations 10-fold. Either bilateral adrenalectomy or demedullation selectively abolished the secondary phase of the pressor response and greatly reduced the plasma CA response to stimulation. After chemical destruction of the terminals of the sympathetic neurones by intravenous administration of 6-hydroxydopamine (6-OHDA), the primary pressor phase was eliminated whereas the secondary phase as well as plasma CA concentration reached higher levels than in normal rats. 6-OHDA treatment combined with adrenalectomy completely abolished both pressor and CA responses. The results demonstrate that adrenomedullary mechanisms capable of increasing blood pressure significantly can be activiated by electrical stimulation of different sites in the diencephalon and mesencephalon.

Axons of passage may be responsible for fastigial nucleus pressor response

1989 ◽  
Vol 257 (6) ◽  
pp. R1436-R1440
Author(s):  
R. T. Henry ◽  
J. D. Connor
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Electrical Stimulation ◽  
Kainic Acid ◽  
Pulse Width ◽  
Pressor Response ◽  
Fastigial Nucleus ◽  
Postural Asymmetry ◽  
Bilateral Destruction ◽  
Stimulation Of

Bilateral destruction of perikarya in the fastigial nucleus (FN) of the rat with the cytotoxic agent kainic acid (0.5 mg) did not alter the blood pressure (BP) increases observed during monopolar electrical stimulation (100 microA, 50 Hz, 0.5-ms pulse width) of this region. BP increases in control animals were 30 +/- 8 mm Hg, whereas BP increased 30 +/- 7 mmHg in kainic acid-lesioned rats. Furthermore, picrotoxin (100 ng) and muscimol (25 ng) microinjected unilaterally into the FN of conscious, unrestrained rats produced postural asymmetry but no change in BP or heart rate. These data suggest that the FN pressor response may be due, at least in part, to stimulation of axons of passage.

A model of dynamic exercise: the decerebrate rat locomotor preparation

1992 ◽  
Vol 72 (1) ◽  
pp. 121-127 ◽  
Author(s):  
T. G. Bedford ◽  
P. K. Loi ◽  
C. C. Crandall
Keyword(s):  
Blood Pressure ◽  
Electrical Stimulation ◽  
Blood Pressure Response ◽  
Pressor Response ◽  
Dynamic Exercise ◽  
Pressure Response ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Decerebrate Rat ◽  
Stimulation Of

The purpose of this study was to develop a dynamic exercise model in the rat that could be used to study central nervous system control of the cardiovascular system. Rats of both sexes were decerebrated under halothane anesthesia and prepared for induced locomotion on a freely turning wheel. Electrical stimulation of the mesencephalic locomotor region (MLR) elicited locomotion at different speeds and gait patterns and increased heart rate and blood pressure. Two maneuvers were performed to illustrate the potential use of the preparation. The first maneuver consisted of muscular paralysis, which prevents excitation of muscle mechanoreceptors and chemoreceptors resulting from exercise. MLR stimulation still increased blood pressure. The second maneuver was performed to determine whether the blood pressure response obtained during paralysis was an artifact of electrical stimulation of the MLR. After microinjection of gamma-aminobutyric acid into the MLR, electrical current thresholds for blood pressure and locomotion increased in parallel. gamma-Aminobutyric acid injection also reduced the pressor response to suprathreshold electrical stimulation by 76%. The injection results suggest that electrical stimulation of the MLR activates cells rather than fibers of passage. The blood pressure response of the exercise model is probably not an artifact of stimulation. The decerebrate rat locomotor preparation should offer another approach to investigate difficult problems in exercise physiology.

Sympathetic alterations after midline medullary raphe lesions

1987 ◽  
Vol 253 (1) ◽  
pp. R91-R100 ◽  
Author(s):  
R. B. McCall ◽  
L. T. Harris
Keyword(s):  
Blood Pressure ◽  
Electrical Stimulation ◽  
Sympathetic Nerve ◽  
Sympathetic Activity ◽  
Sympathetic Nerve Activity ◽  
Pressor Response ◽  
Vagal Afferents ◽  
Nerve Activity ◽  
Medullary Raphe ◽  
Stimulation Of

The present study was designed to determine the functional importance of the midline medullary raphe nuclei in the autonomic regulation of the cardiovascular system in the anesthetized cat. Baroreceptor and somatosympathetic reflexes as well as the effects of electrical stimulation of vagal afferents and pressor and depressor sites in the hypothalamus and spinal trigeminal tract were determined before and after midline medullary lesions that extended from 2 to 7 mm rostral to the obex. Midline medullary lesions failed to affect baroreceptor reflexes as judged by the lack of effect on the sympathoinhibition associated with the pressor response to phenylephrine and the degree of slow-wave locking of sympathetic activity to the cardiac cycle. However, the lesion did significantly increase spontaneous sympathetic activity recorded from the inferior cardiac nerve. Blood pressure and heart rate were not altered by midline lesions. In addition, the computer-summed sympathoexcitatory response to electrical stimulation of somatic afferents in the sciatic nerve and the sympathoinhibitory response to stimulation of vagal afferent fibers were not affected by midline lesions. In contrast, the decrease in blood pressure and inhibition of sympathetic nerve activity elicited by electrical stimulation of the spinal trigeminal tract were completely abolished by the lesion. Depressor responses evoked from the anteroventral third ventricle region of the hypothalamus but not pressor responses elicited from the posterior hypothalamus were eliminated following midline medullary lesions. Finally, the sympathoinhibitory actions of the serotonin antagonist methysergide were blocked by medullary raphe lesions. These data indicate that neural elements in the medial medullary area function to provide a tonic inhibition of sympathetic nerve activity that is of nonbaroreceptor origin. Depressor responses evoked from the anterior hypothalamus and the spinal trigeminal tract also are mediated through this area of the medulla. Finally, the data support our contention that medullary serotonergic neurons have a sympathoexcitatory function.

scholarly journals Deep Brain Stimulation of the Posterior Insula in Chronic Pain: A Theoretical Framework

2021 ◽  
Vol 11 (5) ◽  
pp. 639
Author(s):  
David Bergeron ◽  
Sami Obaid ◽  
Marie-Pierre Fournier-Gosselin ◽  
Alain Bouthillier ◽  
Dang Khoa Nguyen
Keyword(s):  
Chronic Pain ◽  
Electrical Stimulation ◽  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
High Frequency ◽  
Brain Lesion ◽  
Low Frequency ◽  
Posterior Insula ◽  
Deep Brain ◽  
Stimulation Of

Introduction: To date, clinical trials of deep brain stimulation (DBS) for refractory chronic pain have yielded unsatisfying results. Recent evidence suggests that the posterior insula may represent a promising DBS target for this indication. Methods: We present a narrative review highlighting the theoretical basis of posterior insula DBS in patients with chronic pain. Results: Neuroanatomical studies identified the posterior insula as an important cortical relay center for pain and interoception. Intracranial neuronal recordings showed that the earliest response to painful laser stimulation occurs in the posterior insula. The posterior insula is one of the only regions in the brain whose low-frequency electrical stimulation can elicit painful sensations. Most chronic pain syndromes, such as fibromyalgia, had abnormal functional connectivity of the posterior insula on functional imaging. Finally, preliminary results indicated that high-frequency electrical stimulation of the posterior insula can acutely increase pain thresholds. Conclusion: In light of the converging evidence from neuroanatomical, brain lesion, neuroimaging, and intracranial recording and stimulation as well as non-invasive stimulation studies, it appears that the insula is a critical hub for central integration and processing of painful stimuli, whose high-frequency electrical stimulation has the potential to relieve patients from the sensory and affective burden of chronic pain.

Facilitation of female reproductive behavior from mesensephalic central gray in the rat

1979 ◽  
Vol 237 (5) ◽  
pp. R278-R284 ◽  
Author(s):  
Y. Sakuma ◽  
D. W. Pfaff
Keyword(s):  
Electrical Stimulation ◽  
Mesencephalic Reticular Formation ◽  
Female Rats ◽  
Motor Systems ◽  
Functional Link ◽  
Implanted Electrodes ◽  
Unilateral Stimulation ◽  
Postural Changes ◽  
Central Gray ◽  
Stimulation Of

Electrical stimulation in the mesencephalic central gray (CG) and adjacent subtectum through chronically implanted electrodes in free-moving estrogen-primed ovariectomized female rats elicited a rapid and large facilitation of the lordosis reflex in response to either male mounts or manula cutaneous stimuli. Unilateral stimulation was sufficient for this effect. The facilitation increased in a graded manner to increased stimulus intensity, and was optimally evoked by stimuli delivered at 50--150 Hz. Facilitation disappeared rapidly following the end ot electrical stimulation, and within 15 min, reflex performance returned to the prestimulation level. Lordosis facilitation appeared when no aversive responses occurred; stimulation with comparable parameters at the lateral edge of CG or in the mesencephalic reticular formation often resulted in postural changes or aversive responses but was not able to facilitate lordosis. Lordosis refelx facilitation was probably mediated by projections descending from neurons in and around the CG, and represents stimulation of a functional link between ascending somatosensory and descending motor systems for the control of lordosis behavior.

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