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Regulation of basal corticotropin-releasing hormone and arginine vasopressin messenger ribonucleic acid expression in the paraventricular nucleus: effects of selective hypothalamic deafferentations.
Endocrinology 1990; 127(5):2408-17E

Abstract

There exists considerable evidence to suggest that CRH and arginine vasopressin (AVP)-secreting parvocellular neurosecretory neurons of the hypothalamic paraventricular nucleus (PVN) are central integrators of negative feedback effects evoked by circulating glucocorticoid hormones. Most evidence suggests that these neurons may be receptive to circulating glucocorticoid levels, either via glucocorticoid receptors indigenous to these cells and/or via extrahypothalamic glucocorticoid-receptive neurons interacting with the PVN secretory cell. In an effort to address this issue, we performed anterior (ANT), posterior (POST) and total (TOT) deafferentations of the PVN region in male Sprague-Dawley rats using microknives fashioned from narrow-gauge spinal needles. Effective knife cuts were verified immunohistochemically, and deemed acceptable only if they avoided damage to the PVN proper and fibers of CRH and AVP-containing neurons coursing through the hypothalamus en route to the median eminence, while effectively eliminating neuronal input into the PVN region. Subsequent to surgery, levels of mRNA encoding for CRH and AVP in the parvocellular and magnocellular PVN were assayed via semiquantitative in situ hybridization histochemistry. Results indicate that TOT deafferentations resulted in significant increases in CRH mRNA expression in the PVN, and a slight but noticeable induction of AVP mRNA in the medial parvocellular but not posterior magnocellular divisions of the PVN. ANT lesions also produced an up-regulation of CRH and AVP mRNA relative to operated control rats. POST lesions did not produce a clear induction in either CRH or AVP mRNA. The data indicate that in the absence of neuronal input coming from anterior structures, CRH mRNA expression is up-regulated, suggesting that local effects of glucocorticoids on the PVN neuron are ineffective in maintaining normal CRH mRNA expression. These results support a role for neuronal feedback in regulation of the CRH neuron. The limited up-regulation (compared with adrenalectomized rats) of AVP mRNA in the TOT group suggests that while neuronal input may have some control of AVP mRNA expression, local glucocorticoid feedback is clearly able to restrict AVP message to levels considerably less than those seen in steroid-deficient animals. Analysis of knife-cut effects on plasma corticosterone and ACTH levels reveals that POST and TOT, but not ANT, deafferentations prohibit the secretory activity of the hypothalamo-pituitary-adrenocortical (HPA) axis seen pursuant to the anesthesia/thoracotomy in lesion and operated control groups.(

ABSTRACT

TRUNCATED AT 400 WORDS)

Authors+Show Affiliations

Mental Health Research Institute, University of Michigan, Ann Arbor 48109.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

2171915

Citation

Herman, J P., et al. "Regulation of Basal Corticotropin-releasing Hormone and Arginine Vasopressin Messenger Ribonucleic Acid Expression in the Paraventricular Nucleus: Effects of Selective Hypothalamic Deafferentations." Endocrinology, vol. 127, no. 5, 1990, pp. 2408-17.
Herman JP, Wiegand SJ, Watson SJ. Regulation of basal corticotropin-releasing hormone and arginine vasopressin messenger ribonucleic acid expression in the paraventricular nucleus: effects of selective hypothalamic deafferentations. Endocrinology. 1990;127(5):2408-17.
Herman, J. P., Wiegand, S. J., & Watson, S. J. (1990). Regulation of basal corticotropin-releasing hormone and arginine vasopressin messenger ribonucleic acid expression in the paraventricular nucleus: effects of selective hypothalamic deafferentations. Endocrinology, 127(5), pp. 2408-17.
Herman JP, Wiegand SJ, Watson SJ. Regulation of Basal Corticotropin-releasing Hormone and Arginine Vasopressin Messenger Ribonucleic Acid Expression in the Paraventricular Nucleus: Effects of Selective Hypothalamic Deafferentations. Endocrinology. 1990;127(5):2408-17. PubMed PMID: 2171915.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Regulation of basal corticotropin-releasing hormone and arginine vasopressin messenger ribonucleic acid expression in the paraventricular nucleus: effects of selective hypothalamic deafferentations. AU - Herman,J P, AU - Wiegand,S J, AU - Watson,S J, PY - 1990/11/1/pubmed PY - 1990/11/1/medline PY - 1990/11/1/entrez SP - 2408 EP - 17 JF - Endocrinology JO - Endocrinology VL - 127 IS - 5 N2 - There exists considerable evidence to suggest that CRH and arginine vasopressin (AVP)-secreting parvocellular neurosecretory neurons of the hypothalamic paraventricular nucleus (PVN) are central integrators of negative feedback effects evoked by circulating glucocorticoid hormones. Most evidence suggests that these neurons may be receptive to circulating glucocorticoid levels, either via glucocorticoid receptors indigenous to these cells and/or via extrahypothalamic glucocorticoid-receptive neurons interacting with the PVN secretory cell. In an effort to address this issue, we performed anterior (ANT), posterior (POST) and total (TOT) deafferentations of the PVN region in male Sprague-Dawley rats using microknives fashioned from narrow-gauge spinal needles. Effective knife cuts were verified immunohistochemically, and deemed acceptable only if they avoided damage to the PVN proper and fibers of CRH and AVP-containing neurons coursing through the hypothalamus en route to the median eminence, while effectively eliminating neuronal input into the PVN region. Subsequent to surgery, levels of mRNA encoding for CRH and AVP in the parvocellular and magnocellular PVN were assayed via semiquantitative in situ hybridization histochemistry. Results indicate that TOT deafferentations resulted in significant increases in CRH mRNA expression in the PVN, and a slight but noticeable induction of AVP mRNA in the medial parvocellular but not posterior magnocellular divisions of the PVN. ANT lesions also produced an up-regulation of CRH and AVP mRNA relative to operated control rats. POST lesions did not produce a clear induction in either CRH or AVP mRNA. The data indicate that in the absence of neuronal input coming from anterior structures, CRH mRNA expression is up-regulated, suggesting that local effects of glucocorticoids on the PVN neuron are ineffective in maintaining normal CRH mRNA expression. These results support a role for neuronal feedback in regulation of the CRH neuron. The limited up-regulation (compared with adrenalectomized rats) of AVP mRNA in the TOT group suggests that while neuronal input may have some control of AVP mRNA expression, local glucocorticoid feedback is clearly able to restrict AVP message to levels considerably less than those seen in steroid-deficient animals. Analysis of knife-cut effects on plasma corticosterone and ACTH levels reveals that POST and TOT, but not ANT, deafferentations prohibit the secretory activity of the hypothalamo-pituitary-adrenocortical (HPA) axis seen pursuant to the anesthesia/thoracotomy in lesion and operated control groups.(ABSTRACT TRUNCATED AT 400 WORDS) SN - 0013-7227 UR - https://www.unboundmedicine.com/medline/citation/2171915/Regulation_of_basal_corticotropin_releasing_hormone_and_arginine_vasopressin_messenger_ribonucleic_acid_expression_in_the_paraventricular_nucleus:_effects_of_selective_hypothalamic_deafferentations_ L2 - https://academic.oup.com/endo/article-lookup/doi/10.1210/endo-127-5-2408 DB - PRIME DP - Unbound Medicine ER -