Document Detail

Pressor, tachycardic and behavioral excitatory responses in conscious rats following ICV administration of ACTH and CRF are blocked by naloxone pretreatment.
MedLine Citation:
PMID:  3020526     Owner:  NLM     Status:  MEDLINE    
Experiments were conducted to compare the blood pressure and heart rate responses of conscious rats given intracerebroventricular (ICV) injections of adrenocorticotropin (ACTH 1-24) and corticotropin releasing factor (CRF). Under sodium pentobarbital anaesthesia, rats were implanted with a stainless-steel cannula into the lateral cerebral ventricle and had their right femoral artery and vein cannulated. Upon recovery (24-48 hr later) conscious, unrestrained rats were given ICV injections (total volume 5 microliter by gravity flow) of sterile saline, ACTH (1-24) (0.85 and 1.7 nmoles) or CRF (0.55 and 1.1 nmoles) and blood pressure and heart rate were monitored over the next 2 hr (from the abdominal aorta via the femoral arterial catheter). Both ACTH and CRF caused mean arterial pressure (MAP) to increase, which was paralleled with increases in mean heart rate (MHR). Moreover, these elevations in MAP and MHR were temporally associated with excessive grooming (for ACTH) and locomotor activity (for CRF), which occurred before and lasted as long as MAP and MHR were enhanced. Intravenous (IV) pretreatment whereby naloxone was given 10 min before ICV administration of ACTH (1.7 nmoles) or CRF (1.1 nmoles), showed that naloxone blocked the behavioral, pressor and tachycardic effects of both ACTH and CRF. The results demonstrate that the pressor, tachycardic and locomotor effects evoked in conscious rats by ICV administration of ACTH or CRF are antagonized by naloxone and that their hemodynamic changes may, in part, be mediated by prior behavioral activation.
W S Saunders; J A Thornhill
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Peptides     Volume:  7     ISSN:  0196-9781     ISO Abbreviation:  Peptides     Publication Date:    1986 Jul-Aug
Date Detail:
Created Date:  1986-11-20     Completed Date:  1986-11-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8008690     Medline TA:  Peptides     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  597-601     Citation Subset:  IM    
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MeSH Terms
Adrenocorticotropic Hormone / pharmacology*
Blood Pressure / drug effects*
Cerebral Ventricles / drug effects,  physiology*
Corticotropin-Releasing Hormone / administration & dosage,  antagonists & inhibitors,  pharmacology*
Cosyntropin / administration & dosage,  antagonists & inhibitors,  pharmacology*
Grooming / drug effects*
Heart Rate / drug effects*
Injections, Intraventricular
Motor Activity / drug effects*
Naloxone / pharmacology*
Rats, Inbred Strains
Reg. No./Substance:
16960-16-0/Cosyntropin; 465-65-6/Naloxone; 9002-60-2/Adrenocorticotropic Hormone; 9015-71-8/Corticotropin-Releasing Hormone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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