Feedback Effects of Dexamethasone on Adrenocortical Responses in Rats with Fornix Section

Feldman, S.; Conforti, N.

doi:10.1159/000178709

Cited by 39 publications

(10 citation statements)

References 5 publications

(6 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result is consistent with our previous finding [12] that section of the dorsal fornix, which is the efferent pathway of the dorsal hippocampus [26], has a similar effect to that produced by dorsal hippocampec tomy.…”

Section: Discussionsupporting

confidence: 94%

“…In an attempt to determine whether the brain plays a role in the negative feedback of glucocorticoids in the regulation of ACTH secretion, the effects of dexametha sone on adrenocortical responses were compared in intact animals and in rats with hypothalamic deallerentations and brain lesions, which by themselves did not affect the adrenocortical response. It was found that such procedures have in fact modified the feedback effect of the corticoids either by diminishing or enhancing their influence [12][13][14],The hippocampus has been shown to mainly have an inhibitory effect in the regulation of ACTH secretion [2,21,23]. It also plays a role in maintaining the circadian rhythm of the adrenocortical function [27] and mediates adrenocortical responses following somatosensory stimu lation [4], In order to elucidate the possible role of the hippocampus in the feedback influences of glucocorticoids, experiments were performed in rats with selective lesions in the hippocampus and its efferent pathways.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Participation of the Dorsal Hippocampus in the Glucocorticoid Feedback Effect on Adrenocortical Activity

Feldman¹,

Conforti²

1980

Neuroendocrinology

194

View full text Add to dashboard Cite

The feedback effect of systemically administered dexamethasone on basal plasma corticosterone levels and on adrenocortical responses to ether plus skin incision stress were studied in intact rats and in animals with bilateral dorsal or ventral hippocampectomy or fimbria section. It was found that in rats with ventral hippocampectomy or fimbria section, the degree of the feedback was similar to that in intact rats. However, in animals with dorsal hippocampectomy, the inhibitory effect of dexamethasone on basal and stress-induced adrenocortical responses was significantly reduced. These results taken together with previous observations, that section of the dorsal fornix has a similar effect, suggest that dexamethasone exerts its influence on the brain and that the dorsal hippocampal formation participates in the feedback regulation of pituitary-adrenal function. It cannot be excluded, however, that dexamethasone may exert its influence on the pituitary, and the effect observed may be summation of dexamethasone action on the pituitary plus lack of hippocampal input.

show abstract

Section: Discussionsupporting

confidence: 94%

mentioning

confidence: 99%

Participation of the Dorsal Hippocampus in the Glucocorticoid Feedback Effect on Adrenocortical Activity

Feldman¹,

Conforti²

1980

Neuroendocrinology

194

View full text Add to dashboard Cite

show abstract

“…It is possible that the in creased glucose metabolism observed in the hippocampus is a reflection of the increased activity set forth by the disinhibition of hippocampal neurons, a putative site of nega tive-feedback inhibition by circulating glucocorticoids [30,46). Lesion of the entire hippocampus, or of the fornix, atte nuates the suppressive effects of dexamethasone upon the stress response [9,10,49). Dexamethasone treatment pre vents the increased glucose metabolism in the hippocampus following adrenalectomy.…”

Section: Discussionmentioning

confidence: 99%

Local Cerebral Glucose Utilization Is Increased in Acutely Adrenalectomized Rats

Kadekaro

Ito

Gross³

1988

Neuroendocrinology

156

View full text Add to dashboard Cite

The quantitative autoradiographic deoxyglucose method was used to study the effects of acute adrenalectomy on local cerebral glucose utilization in conscious albino rats. Five hours following removal of the adrenal glands, glucose utilization was increased (4–55%) throughout the brain, particularly in the locus ceruleus, hypothalamic paraventricular nucleus, hippocampus, median eminence and anterior lobe of the pituitary gland. These structures are involved in the regulation of corticotropin-releasing factor, vasopressin, and adrenocorticotropic hormone. Treatment with dexametha-sone (0.25 mg/kg i.m.) substantially reduced or prevented the stimulatory effects of adrenalectomy on cerebral glucose metabolism. These results demonstrate: (1) the existence of a negative feedback loop between the brain and adrenal glands in which corticosteroids exert an inhibitory action on glucose utilization of brain regions participating in adrenotropic regulation, and (2) a general inhibitory action of glucocorticoids on cerebral metabolism.

show abstract

“…21 In addition, glucocorticoids can bind their cognate receptors in hippocampus to activate indirect pathways leading to suppression of hypothalamic CRH mRNA expression. [22][23][24] The limbic neuroendocrine and behavioral circuit A second major stress-transducing circuit consists of limbic pathways that are more sensitive to stressors involving higher-order sensory processing ( Figure 1b). [25][26][27] These pathways are preferentially activated by stimuli that require assembly and processing of signals from multiple modalities (as opposed to stressors that are an immediate physiological threat).…”

Section: Neuronal Circuitry and Crh-mediated Transduction Of The Respmentioning

confidence: 99%

Neurobiology of the stress response early in life: evolution of a concept and the role of corticotropin releasing hormone

et al. 2001

View full text Add to dashboard Cite

Over the last few decades, concepts regarding the presence of hormonal and molecular responses to stress during the first postnatal weeks in the rat and the role of the neuropeptide corticotropin releasing hormone (CRH) in these processes, have been evolving. CRH has been shown to contribute critically to molecular and neuroendocrine responses to stress during development. In turn the expression of this neuropeptide in both hypothalamus and amygdala is differentially modulated by single and recurrent stress, and is determined also by the type of stress (eg, psychological or physiological). A likely transcriptional regulatory factor for modulating CRH gene expression, the cAMP responsive element binding protein CREB, is phosphorylated (activated) in the developing hypothalamus within seconds of stress onset, preceding the transcription of the CRH gene and initiating the activation of stress-induced cellular and neuroendocrine cascades. Finally, early life stress may permanently modify the hypothalamic pituitary adrenal axis and the response to further stressful stimuli, and recent data suggest that CRH may play an integral role in the mechanisms of these long-term changes. Molecular Psychiatry (2001) 6, 647-656.

show abstract

Feedback Effects of Dexamethasone on Adrenocortical Responses in Rats with Fornix Section

Cited by 39 publications

References 5 publications

Participation of the Dorsal Hippocampus in the Glucocorticoid Feedback Effect on Adrenocortical Activity

Participation of the Dorsal Hippocampus in the Glucocorticoid Feedback Effect on Adrenocortical Activity

Local Cerebral Glucose Utilization Is Increased in Acutely Adrenalectomized Rats

Neurobiology of the stress response early in life: evolution of a concept and the role of corticotropin releasing hormone

Contact Info

Product

Resources

About