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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neuroendocrinology 8 (1996), S. 0 
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The role of afferent innervation to the hypothalamic paraventricular nucleus (PVN) on CRH mRNA and CRH receptor mRNA levels was studied in control and stressed rats. Groups of rats were subjected to unilateral transection of the stria terminalis (ST), the medial forebrain bundle at the rostral hypothalamic level (RMFB), or the lower brainstem through the medulla oblongata between the obex and the locus coeruleus (CBs). Twelve days after surgery, each group of rats was further divided into controls (basal conditions) and stressed (1 h immobilization), before collecting brains for mRNA analysis by in situ hybridization histochemistry. While ST and RMFB cuts had no effect on basal CRH mRNA levels in the PVN, CBs cut decreased CRH mRNA in the PVN ipsilaterally to the knife cut but it was without effect on the contralateral side (– 40% and –37%vs contralateral and sham-operated, respectively, P&0.01). Acute stress (rats were killed 3 h after immobilization) increased CRH mRNA levels by about 30% bilaterally, an effect which was unchanged by any of the three hemisections. Under basal conditions, CRH receptor mRNA levels in the PVN were indistinguishable from the surrounding areas in sham-operated controls, ST and RMFB operated rats. However, brainstem hemisection resulted in clear expression of CRH receptor mRNA in areas consistent with the dorsal, medial-ventral and lateral parvicellular subdivisions of the PVN, ipsilateral to the transection. CRH neurons in these subdivisions project to the lower brainstem and the spinal cord. Expression of CRH receptor mRNA in the medial-dorsal and anterior parvicellular divisions (CRH neurons with median eminence projections) was not affected by CBs cut. In these subdivisions, immobilization stress markedly increased CRH receptor mRNA levels but it did not influence CBs cut-induced CRH receptor expression. ST and RMFB hemisections were without effect on PVN CRH receptor mRNA levels under basal or stress conditions. Oxytocin (OT) and vasopressin (VP) mRNA levels in the magnocellular subdivision of the PVN were unchanged after immobilization, or following ST, RMFB or CBs cuts, whereas OT mRNA in the medial-ventral and caudal parvicellular subdivisions was decreased by 52% after CBs cut. The data demonstrate that: 1) basal CRH mRNA levels in the PVN are under tonic stimulatory influence of the lower brainstem (and/or spinal cord) afferents; 2) CRH receptor mRNA expression in PVN subdivisions (pituitary vs lower brainstem/spinal cord projecting neurons) is under different control mechanisms, and 3) immobilization-induced changes in CRH mRNA and CRH receptor mRNA levels are mediated either by neural inputs from brain areas other than those investigated here, or by humoral factors.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neuroendocrinology 5 (1993), S. 0 
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Increases in plasma VP in response to osmotic stimulation are critical for water conservation, while VP released into the pituitary portal circulation is an important regulator of ACTH secretion and does not contribute to plasma VP levels. The role of the adrenal medulla in the specificity of these responses was studied in rats subjected to osmotic and non-osmotic stress two months following adrenal demedullation or sham operation. Basal and stimulated plasma corticosterone, aldosterone, ACTH and PRA levels in adrenal demedullated rats were similar to those in the sham operated groups indicating recovery of adrenocortical function. Basal plasma VP levels were similar in sham operated controls and adrenal demedullated rats (0.93±0.13 and 1.0 ± 0.1 pg/ml, respectively) and rose to comparable levels in both groups following 48 h osmotic stimulation by water deprivation (14.4+1.3 and 20.7 + 3.4, respectively). On the other hand, while in sham operated rats, immobilization for 15 min, a non-osmotic stress, had no effect on plasma VP levels in control or water deprived (2.0±0.9 and 15.0±2.7 pg/ml), in adrenal demedullated rats, caused dramatic increases in plasma VP from 1.0±0.1 to 126.0 + 29.9 pg/ml in controls, and from 20.7 + 3.4 to 155 + 37 pg/ml in water deprived rats. Intraperitoneal hypertonic saline injection, a combination of osmotic and painful stress, caused much higher increases in plasma VP in adrenal demedullated rats (138.0 + 22.1 compared with 34.7 + 3.7 pg/ml in sham operated rats). Water deprivation potentiated this response to 70.0 + 8.3 and 295 + 24 pg/ml in sham operated and adrenal demedullated rats, respectively. VP mRNA measured by in situ hybridization, and irVP measured by immunohistochemistry, were elevated in magnocellular neurones in the hypothalamus of adrenal demedullated rats. The demonstration of marked plasma VP responses to non-osmotic stimuli in adrenal demedullated rats, suggests a modulatory role for the adrenal medulla in the specificity of the secretory responses of the magnocellular and parvicellular vasopressinergic systems.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neuroendocrinology 7 (1995), S. 0 
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Double staining in situ hybridization studies have shown that angiotensin II (All) type 1 receptors (AT1) in the hypothalamic paraventricular nucleus (PVN) are located primarily in corticotropin releasing hormone (CRH) neurons of the parvicellular subdivision. The purpose of these studies was to investigate the role of All regulating the hypothalamic-pituitary adrenal (HPA) axis, by correlating AT1 receptor expression levels in the PVN with the known changes in activity of the HPA axis under different stress paradigms, and manipulation of circulating glucocorticoids. AT1 receptor mRNA was measured by in situ hybridization using 35S-labelled cRNA probes and All binding by autoradiography using 125I[Sar1,lle8]All in slide mounted hypothalamic sections. AT1 receptor mRNA levels and All binding in the PVN were reduced by about 20% 18 h after adrenalectomy remaining at these levels up to 6 days after. This effect was prevented by corticosterone administration in the drinking water, or dexamethasone injection (100 mg, s.c., daily). Conversely, dexamethasone injection in intact rats caused a 20% increase in AT1 receptor mRNA in the PVN. AT1 receptor mRNA and binding in the PVN increased 4 h after exposure to stress paradigms associated with activation of the HPA axis (immobilization for 1 h, or i.p. injection of 1.5 M NaCl), and remained elevated after repeated daily stress for 14 days. Unexpectedly, two osmotic stress models associated with inhibition of the HPA axis (60 h water deprivation or 12 days of 2% saline intake) also resulted in increased AT1 receptor mRNA levels and All binding in the parvicellular PVN. In intact rats, the stimulatory effect of acute stress on AT1 receptor mRNA in the PVN was significantly enhanced by dexamethasone administration (100 μg, s.c., 14 h and 1 h prior to stress), while in adrenalectomized rats, with or without glucocorticoid replacement, stress reduced rather than increased, AT1 receptor mRNA. Dexamethasone, 100 μg, injected sc within 1 min the beginning of immobilization in adrenalectomized rats, increased AT1 receptor mRNA in the PVN to levels significantly higher than those after dexamethasone alone, indicating that the stress induced glucocorticoid surge is required for the stimulatory effect of stress on AT1 receptor mRNA. The data suggest that AT1 receptor expression in the PVN is under dual control during stress: stress-activated inhibitory pathways and the stimulatory effect of glucocorticoids. The lack of specificity of the changes in AT1 receptor expression in the PVN following stressors with opposite effects on ACTH secretion (osmotic and physical-psychological stress) does not support a role for All as a major determinant of the response of the HPA axis during stress.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Corticotropin releasing hormone (CRH), a major regulator of pituitary ACTH secretion, also acts as a neurotransmitter in the brain. To determine whether CRH is involved in the regulation of hypothalamic function during stress, CRH receptor binding and CRH receptor mRNA levels were studied in the hypothalamus of rats subjected to different stress paradigms: immobilization, a physical-psychological model; water deprivation and 2% saline intake, osmotic models; and i.p. hypertonic saline injection, a combined physical-psychological and osmotic model. In agreement with the distribution of CRH receptor binding in the brain, in situ hybridization studies using 35S-labeled cRNA probes revealed low levels of CRH receptor mRNA in the anterior hypothalamic area, which were unaffected after acute or chronic exposure to any of the stress paradigms used. Under basal conditions, there was no CRH binding or CRH receptor mRNA in the supraoptic (SON) or paraventricular (PVN) nuclei. However, 2 h after the initiation of acute immobilization, CRH receptor mRNA hybridization became evident in the parvicellular division of the PVN, with levels substantially increasing from 2 to 4 h, decreasing at 8 h and disappearing by 24 h. Identical hybridization patterns of CRH receptor mRNA were found in the parvicellular PVN after repeated immobilization; levels were similar to those after 2 h single stress following immobilization at 8-hourly intervals for 24 h (3 times), and very low, but clearly detectable 24 h after 8 or 14 days daily immobilization for 2 h. On the other hand, water deprivation for 24 or 60 h and intake of 2% NaCI for 12 days induced expression of CRH receptor mRNA in the SON and magnocellular PVN, but not in the parvicellular pars of the PVN. Both parvicellular and magnocellular hypothalamic areas showed CRH receptor mRNA following i.p. hypertonic saline injection, single (4 h after) or repeated at 8-hourly intervals for 24 h (3 injections), or one injection daily for 8 or 14 days. Consistent with the expression of CRH receptor mRNA, autoradiographic studies showed binding of 125I-Tyr-oCRH in the parvicellular division of the PVN after immobilization; in the magnocellular division of the PVN after osmotic stimulation, and in the PVN and SON after i.p. hypertonic saline injection. The data show that stress-specific activation of the parvicellular and magnocellular systems is associated with CRH receptor expression, and suggest a role for CRH in the autoregulation of hypothalamic function.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 10 (1998), S. 0 
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Angiotensin II (Ang II) type-1 (AT1) receptors are present in areas of the brain controlling autonomic nervous activity and the hypothalamic-pituitary-adrenal (HPA) axis, including CRH cells in the hypothalamic paraventricular nucleus (PVN). To determine whether brain AT1 receptors are involved in the activation of the HPA axis and sympathetic system during stress, we studied the effects of acute immobilization stress on plasma catecholamines, ACTH and corticosterone, and mRNA levels of CRH and CRH receptors (CRH-R) in the PVN in rats under central AT1 receptor blockade by the selective antagonist, Losartan. While basal levels of epinephrine, norepinephrine and dopamine in plasma were unaffected 30 min after icv injection of Losartan (10 μg), the increases after 5 and 20 min stress were blunted in Losartan treated rats (P〈0.05 for norepinephrine, and P〈0.01 for epinephrine and dopamine, vs controls). Basal or stress-stimulated plasma ACTH and corticosterone levels were unaffected by icv Losartan treatment. Using in situ hybridization studies, basal levels of CRH mRNA and CRH-R mRNA in the PVN were unchanged after icv Losartan. While Losartan had no effect on the increases in CRH-R mRNA levels 2 or 3 h after 1 h immobilization, it prevented the increases in CRH mRNA. The blunted plasma catecholamine responses after central AT1 receptor blockade indicate that endogenous Ang II in the brain is required for sympathoadrenal activation during immobilization stress. While Ang II appears not to be involved in the acute secretory response of the HPA axis, it may play a role in regulating CRH expression in the PVN.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 771 (1995), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0460
    Keywords: Achalasia, symptoms ; Achalasia, diagnosis ; Achalasia, anorexia nervosa ; Achalasia, bulimia nervosa ; Dysphagia ; Deglutition ; Deglutition disorders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The case of a young women with dysphagia, regurgitation, and weight loss, who was diagnosed as having anorexia nervosa but in whom reevaluation showed that achalasia was causing the symptoms, is presented together with related observations. Misinterpretation of esophageal symptoms may occur not only as a consequence of inadequate history taking and of being biased by a patient's emaciation, age, and gender, which leads to view certain aspects of the patient's history and behavior as suggesting a pathologic attitude towards eating and body weight, but also as a consequence of a misinterpretation of the symptoms as indicative of an eating disorder by the patients themselves. In some cases a disordered attitude toward eating and body weight may develop together or coexist with achalasia. The clinical evaluation of patients with symptoms suggestive of anorexia nervosa but also of bulimia nervosa should include the taking of a thorough history regarding swallowing and vomiting in order to recognize a possible esophageal motor disorder.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Supportive care in cancer 3 (1995), S. 1-2 
    ISSN: 1433-7339
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular histology 30 (1998), S. 569-575 
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The aim of the present study was to verify the hypothesis that stress exposure modifies the content and release of galanin in the hypothalamic paraventricular nucleus and the median eminence. Colchicine and immobilization served as stress stimuli, and the changes in galanin immunoreactivity were compared with those in corticotropin-releasing hormone and vasopressin. In control animals, a limited number of galanin perikarya were identified in the paraventricular nucleus. The high dose (75 μg) of colchicine enhanced galanin in both parvicellular and magnocellular subdivisions, as analysed 72 h later. In the median eminence, galanin accumulated only in the external zone. High- dose colchicine did not affect galanin, while corticotropin- releasing hormone and vasopressin were depleted from the median eminence. Immobilization (120 min) neither alone nor in combination with colchicine influenced galanin immuno-reactivity in the external zone. The low dose of colchicine induced an unexpected accumulation of galanin in the internal zone of the median eminence, which was further increased by subsequent immobilization. In the external zone, low-dose colchicine induced a complete disappearance of vasopressin, substantial depletion of corticotropin-releasing hormone and no changes in galanin immunoreactivity. The present studies demonstrate that galanin in the external zone of the median eminence is not influenced by colchicine or by immobilization stress.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-6830
    Keywords: alpha-adrenergic ; corticotropin-releasing hormone ; HPA axis ; hypothalamic paraventricular nucleus ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract SUMMARY 1. The role of α1-adrenergic receptors on CRH mRNA levels in the PVN was studied in control and stressed rats receiving i.c.v. injections of the α1-adrenergic agonist, methoxamine, or the α1- antagonist, prazosin. 2. Plasma ACTH increased significantly 60 min and 4 hr after a single injection of methoxamine (100 μg, i.c.v.). No desensitization of this response was observed after repeated injections every 6 hr for 24 hr. Concomitantly, POMC mRNA in the anterior pituitary increased by 25% at 4 hr after a single injection and by 96% after repeated injections. 3. CRH mRNA levels in the PVN increased by 131% after repeated injections for 24 hr, but were unchanged 4 hr after a single injection. Central α1-adrenergic blockade with prazosin did not prevent the increases in CRH mRNA following 4 hr of acute stress, but significantly reduced the increases observed 24 hr after an i.c.v. injection of 75 μg of colchicine or after repeated i.p. hypertonic saline injections every 8 hr. 4. These studies demonstrate that while α1-adrenergic receptors contribute to long-term increases of CRH mRNA levels in the PVN during prolonged stress, other factors are likely to be involved in the stimulation of CRH mRNA following acute stimulation.
    Type of Medium: Electronic Resource
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