Catecholaminergic Mechanisms-Mediated Hypothermia Induced by Magnolol in Rats

Temporal changes in monoaminergic activity in the locus coeruleus (LC) in response to hemorrhage of 10 or 20% of blood volume were assessed using normal pulse voltammetry in alpha-chloralose-urethan-anesthetized cats. Oxidation current was measured with a carbon microelectrode, and changes at 230 and 450 mV were used as estimates of catecholaminergic and indolaminergic activity, respectively. Plasma adrenocorticotropin (ACTH) was measured by radioimmunoassay. Hemorrhage of 20% blood volume caused a transient increase in the catecholaminergic activity in a compact area in the ventral LC (vLC) that preceded increases in the plasma ACTH. The increase in oxidation current at 450 mV was similar to that at 230 mV, suggesting no significant contribution from indolamines. Dorsal rostral pontine sites outside this area exhibited either sustained decreases in oxidation current or no change in response to hemorrhage. The proportion of sites that exhibited transient increases in oxidation current in the vLC after the 10% blood loss was less than that after the 20% blood loss, suggesting that this response was dependent on the magnitude of hemorrhage. Since the LC was implicated previously in the control of ACTH release, we suggest that hemodynamic signals traversing the LC activate catecholaminergic mechanisms that, in turn, participate in the regulation of ACTH release after hemorrhage.

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DIENCEPHALIC INVOLVEMENT IN GENERALIZED LIPODYSTROPHY: RATIONALE AND TREATMENT WITH THE NEUROLEPTIC AGENT, PIMOZIDE

Acta Endocrinologica ◽

10.1530/acta.0.0770209 ◽

1974 ◽

Vol 77 (2) ◽

pp. 209-220 ◽

Cited By ~ 22

Author(s):

Alan Corbin ◽

G. Virginia Upton ◽

C. C. Mabry ◽

Dorothy R. Hollingsworth

Keyword(s):

General Circulation ◽

Subcutaneous Fat ◽

Well Being ◽

Blood Chemistry ◽

Peripheral Circulation ◽

Blocking Agent ◽

Corticotrophin Releasing Factor ◽

Neuroleptic Agent ◽

Catecholaminergic Mechanisms ◽

Dopaminergic Blocking

ABSTRACT Our results indicate that generalized lipodystrophy (GLD) possesses as one of its manifestations, diencephalic neuroendocrinopathy. It has been postulated that deranged hypothalamic catecholaminergic mechanisms lead to the hypersecretion of hypophysiotrophic hormones that are detectable in the peripheral circulation. Initial treatment of a pre-puberal GLD patient with chlorpromazine was unrewarding. Chronic treatment of the same patients with the selective dopaminergic blocking agent, pimozide, eliminated corticotrophin releasing factor and luteinizing hormone releasing factor activities from the general circulation. Pimozide treatment ameliorated most of the distorted blood chemistry profile, led to return of facial subcutaneous fat, and elimination of cutaneous hyperpigmentation, fever, abdominal pain, hypertrichosis, oilness of hair, scaliness of skin and to a state of general well-being. The results of these studies, structured within the framework of our present knowledge concerning hypothalamic neurotransmitter/releasing hormone physiology, support the concept of diencephalic involvement in GLD and may provide a guideline to effective therapy.

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Evidence for the involvement of central catecholaminergic mechanisms in mediating the preovulatory surge of luteinizing hormone in the domestic hen

Journal of Endocrinology ◽

10.1677/joe.0.0940295 ◽

1982 ◽

Vol 94 (2) ◽

pp. 295-304 ◽

Cited By ~ 14

Author(s):

P. G. Knight ◽

S. C. Wilson ◽

R. T. Gladwell ◽

F. J. Cunningham

Keyword(s):

Steady State ◽

Luteinizing Hormone ◽

Pharmacological Treatments ◽

Ovulatory Cycle ◽

Lh Surge ◽

Dopaminergic Mechanisms ◽

Lh Release ◽

Noradrenaline And Adrenaline ◽

Domestic Hen ◽

Catecholaminergic Mechanisms

The effects of various pharmacological treatments, designed to perturb central catecholaminergic neurotransmission, on the pattern of LH release during the preovulatory period in the domestic hen were studied. Treatment of hens with either l-dihydroxyphenylalanine or diethyldithiocarbamate which raised the concentration of dopamine in the hypothalamus by 42 and 110% respectively, or with apomorphine, attenuated the preovulatory surge of LH. In contrast, treatment with either α-methyl-p-tyrosine which produced a 65% decline in the concentration of dopamine in the hypothalamus without affecting the concentrations of noradrenaline or adrenaline or treatment with pimozide did not affect the LH surge. While treatment with propranolol was similarly ineffective, phenoxybenzamine attenuated the LH surge to a marked extent. These observations suggest that the preovulatory surge of LH in the hen is influenced by facilitatory α-adrenergic and inhibitory dopaminergic mechanisms. Evidence to corroborate these findings was sought by determining the steady-state concentrations of dopamine, noradrenaline and adrenaline in five discrete diencephalic regions of the hen throughout the ovulatory cycle.

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