Diagnostic exercise: peracute death in a research dog.
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Animals↗
Biomedical subjects
V K Bergdall
Publications and source records attributed to V K Bergdall.
Increases in adrenolumbar venous flow and epinephrine secretion elicited by preoptic and hypothalamic stimulation in the cat.
Seventy-five sites were electrically stimulated within the preoptic and hypothalamic areas of anesthetized cats (n = 16). Adrenolumbar venous blood flow, secretion of epinephrine and norepinephrine, heart rate and mean arterial blood pressure were measured at baseline and following a standard stimulus (0.6 mA for 30 s) at each site. The most frequent adrenal medullary response to central stimulation was an increase in the secretion of both catecholamines (ng/min) greater than 10% of the baseline mean. Seventeen sites (23%) increased adrenolumbar venous flow greater than 12% above the mean baseline flow rate. This group of sites also evoked significantly greater increases in the secretion of epinephrine, and in mean arterial blood pressure and heart rate. These data support the hypothesis that secreted catecholamines, especially epinephrine, may act locally to increase blood flow through the adrenal medulla.
Adrenal Medulla↗
Increases in plasma catecholamines during naturally elicited defensive behavior in the cat.
Defensive behavior was evoked in 12 adult cats by the presentation of both interspecific (barking dog) and intraspecific (hypothalamically stimulated cat) stimuli. Each stimulus was presented 3 times. Concomitant activation of the sympatho-adrenal (SA) system was evaluated by radioenzymatic assay of plasma norepinephrine (NE) and epinephrine (E). The somatic and autonomic displays which accompanied defensive behavior were similar between stimuli, consisting of mydriasis, piloerection, growling, hissing and paw strikes. However, the sympatho-adrenal responses associated with interspecific and intraspecific defensive behaviors were different. Interspecific defensive behavior was accompanied by adrenal medullary release of both NE and E, which decreased with successive trials. Intraspecific defensive behavior was initially associated with release of E from the adrenal medulla; the pattern of catecholamine release in successive trials suggested that in later trials NE was released primarily from the sympathetic nerves. Furthermore, increases in plasma NE and E, as well as increases in heart rate and mean arterial blood pressure during the first trial were significantly greater when the behavioral stimulus was a dog. Although aspects of the feline display to threatening stimuli are stereotyped, the data suggest that the sympatho-adrenal response is more specific, and indicates preparation for fighting or escape.
Animals↗
Plasma catecholamines associated with hypothalamically-elicited flight behavior.
Hypothalamic sites were selected which elicited flight (escape) behavior in the freely moving cat. Sympatho-adrenal (SA) activation was determined by measuring the levels of norepinephrine (NE) and epinephrine (E) in bilateral adrenolumbar and peripheral venous plasma following stimulation of these 29 hypothalamic sites in 18 anesthetized cats. Heart rate (HR) and mean arterial pressure (MAP) were continuously monitored to permit comparisons between SA and cardiovascular (CV) activation. The most frequent SA response was a bilateral increase in the output of NE and E from the adrenal medulla greater than or equal to 10 ng/min. Increases in MAP during hypothalamic stimulation were significantly correlated with bilateral increases in both adrenal CAs, while increases in HR were significantly correlated with increases in peripheral venous NE. The data suggest that hypothalamic regions which elicit flight behavior overlap with regions that activate the adrenal medullary and CV systems. The SA activation that accompanied hypothalamically-elicited escape is compared to SA activation associated with hypothalamically-elicited affective defense.
Adrenal Medulla↗
Plasma catecholamines associated with hypothalamically-elicited defense behavior.
Sympatho-adrenal (SA) activation was determined by measuring levels of norepinephrine (NE) and epinephrine (E) in bilateral adrenal venous and peripheral venous plasma of 20 anesthetized cats following stimulation of medial hypothalamic sites. Hypothalamic sites were selected that elicited affective defense behavior in the freely moving cat. Fifty-eight percent of these hypothalamic sites elicited a bilateral increase greater than or equal to 10 ng/min in the output of both adrenal catecholamines (CAs); these increases were greater from the gland ipsilateral to the side of stimulation. Other SA responses included both preferential increases or decreases in either NE or E. Under baseline conditions, an average of 67% of the NE in the peripheral venous plasma was contributed by the sympathetic noradrenergic nerves; hypothalamic stimulation at "defense" sites increased the contribution to 75%. The data suggest that hypothalamic regions that elicit defense behaviour may overlap with regions that activate the adrenal medullary and sympathetic nervous systems.
Adrenal Medulla↗
Increases in blood flow from the adrenal gland following medial hypothalamic stimulation in the cat.
Medial hypothalamic sites previously shown to elicit either flight or defense were stimulated in the anesthetized cat. The rate of blood flow from the adrenolumbar (AL) vein ipsilateral to the side of stimulation was measured, as well as the adrenal output of norepinephrine and epinephrine (E). Stimulation at nearly 15% of the hypothalamic sites increased ipsilateral AL venous flow more than 20% over baseline rates. These sites also significantly increased heart rate, mean arterial pressure, and output of E from the ipsilateral adrenal gland. These observations suggest that hypothalamic sites where stimulation increased AL venous flow may overlap with regions that selectively mediate the release of E from the adrenal medulla.
Adrenal Glands↗
Effects of nerve growth factor infusion on behavioral recovery and graft survival following intraventricular adrenal medulla grafts in the unilateral 6-hydroxydopamine lesioned rat.
NGF was infused into the lateral ventricle of rats with unilateral 6-OHDA lesions of the substantia nigra along with adrenal medulla or control grafts. Treatment effectiveness, as measured by amphetamine-induced turning behavior, indicated that there were no significant differences between treated and control groups in spite of the survival of tyrosine hydroxylase (TH) immunoreactive grafts. Furthermore, adrenal medulla graft survival was not dependent on NGF infusion. These results indicate that TH-positive graft survival is not correlated with behavioral recovery as assessed by amphetamine-induced turning. These results differ from studies which utilized apomorphine-induced turning as a measure of behavioral recovery. We propose that adrenal medulla graft survival alone is not sufficient to promote behavioral recovery in the 6-OHDA lesioned rat.
Adrenal Medulla↗