The effects of hydrogenated ergot alkaloids on the neuronal organization of the central vasomotor control mechanisms in the brain stem of cats

✓ The Kölliker-Fuse nucleus (KF) in the dorsolateral pons has been shown to be the major source of catecholamine innervation of the spinal cord. This has important implications in terms of pain control mechanisms, since catecholamine-mediated mechanisms are essential for the expression of opiate and other varieties of antinociception. This study examines the effects of KF stimulation on responses of dorsal-horn cells to innocuous and noxious cutaneous stimuli in anesthetized cats. Stimulation of the KF potently inhibits the responses of dorsal-horn cells to both noxious and innocuous stimuli. The threshold for the inhibitory effect is significantly lower for responses to noxious stimuli as opposed to innocuous stimuli. The inhibitory effect is specific to the stimulus site, as evidenced by a marked decrease in the effect following small changes in the position of the stimulating electrode in the brain stem. The latency of the effects indicates a bulbospinal conduction velocity of 4 to 5 m/sec, which is much slower than usual reticulospinal effects and is consistent with a catecholamine-mediated system. The dependence of KF-spinal inhibition on intact biogenic amines was tested by depleting the animals of these amines with reserpine pretreatment. Depletion of biogenic amines resulted in a significant decrease in the KF spinal inhibitory effects, suggesting their dependence on intact noradrenergic stores. The results of these studies are consistent with the idea that the KF-spinal system plays an important noradrenergic-dependent role in the brain-stem modulation of spinal processing of noxious, potentially painful stimuli.

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Permeability of the microcirculation in area postrema of rat

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103802 ◽

1988 ◽

Vol 46 ◽

pp. 348-349

Author(s):

Shams M. Ghoneim ◽

Frank M. Faraci ◽

Gary L. Baumbach

Keyword(s):

Brain Stem ◽

Area Postrema ◽

Upper Body ◽

Sprague Dawley ◽

Sodium Cacodylate ◽

Acute Hypertension ◽

Sprague Dawley Rats ◽

Ultrastructural Characteristics ◽

The Brain ◽

Adjacent Brain

The area postrema is a circumventricular organ in the brain stem and is one of the regions in the brain that lacks a fully functional blood-brain barrier. Recently, we found that disruption of the microcirculation during acute hypertension is greater in area postrema than in the adjacent brain stem. In contrast, hyperosmolar disruption of the microcirculation is greater in brain stem. The objective of this study was to compare ultrastructural characteristics of the microcirculation in area postrema and adjacent brain stem.We studied 5 Sprague-Dawley rats. Horseradish peroxidase was injected intravenously and allowed to circulate for 1, 5 or 15 minutes. Following perfusion of the upper body with 2.25% glutaraldehyde in 0.1 M sodium cacodylate, the brain stem was removed, embedded in agar, and chopped into 50-70 μm sections with a TC-Sorvall tissue chopper. Sections of brain stem were incubated for 1 hour in a solution of 3,3' diaminobenzidine tetrahydrochloride (0.05%) in 0.05M Tris buffer with 1% H2O2.

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Surgical Approaches to the Brain Stem

Neurosurgery Clinics of North America ◽

10.1016/s1042-3680(18)30570-9 ◽

1993 ◽

Vol 4 (3) ◽

pp. 457-468 ◽

Cited By ~ 16

Author(s):

Dennis Y. Wen ◽

Roberto C. Heros

Keyword(s):

Brain Stem ◽

Surgical Approaches ◽

The Brain

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Review of The Brain Stem of the Cat: A Cytoarchitectonic Atlas with Stereotaxic Coordinates.

Contemporary Psychology ◽

10.1037/009800 ◽

1969 ◽

Vol 14 (8) ◽

pp. 449-449

Author(s):

GARTH J. THOMAS

Keyword(s):

Brain Stem ◽

The Brain

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ADRENERGIC INPUTS TO THE AMYGDALA AND THE CONTROL OF GONADOTROPHIN RELEASE

Acta Endocrinologica ◽

10.1530/acta.0.0900385 ◽

1979 ◽

Vol 90 (3) ◽

pp. 385-393 ◽

Cited By ~ 5

Author(s):

José Borrell ◽

Flavio Piva ◽

Luciano Martini

Keyword(s):

Brain Stem ◽

Dopamine Receptor ◽

Serum Levels ◽

Female Rats ◽

Receptor Blocker ◽

Dopaminergic Drug ◽

Gonadotrophin Secretion ◽

Biphasic Effect ◽

Adrenergic Blocker ◽

The Brain

ABSTRACT Drugs able to mimic or to antagonize the action of catecholamines have been implanted bilaterally into the basomedial region of the amygdala of adult castrated female rats. The animals were killed at different intervals after the implantation of the different drugs, and serum levels of LH and FSH were measured by radioimmunoassay. The results have shown that the intra-amygdalar implantation of the alpha-adrenergic blocker phenoxybenzamine induces a significant increase of the release both of LH and FSH. The implantation of the beta-adrenergic blocker propranolol brings about a rise of LH only. The dopamine receptor blocker pimozide stimulates the release of LH and exerts a biphasic effect (stimulation followed by inhibition) of FSH secretion. The alpha-receptor stimulant clonidine and the dopaminergic drug 2-Br-alpha-ergocryptine were without significant effects. From these observations it is suggested that the adrenergic signals reaching the basomedial area of the amygdala (possibly from the brain stem) may be involved in the modulation of gonadotrophin secretion.

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