Document Detail

Effects of antihypertensive drugs on ultrasound production and cardiovascular responses in 15-day-old rats.
MedLine Citation:
PMID:  11844570     Owner:  NLM     Status:  MEDLINE    
When exposed to extreme cold or injected with the alpha(2)-adrenoceptor agonist, clonidine, infant rats emit ultrasonic vocalizations (USVs). Based upon the cardiovascular changes that accompany these two manipulations, especially decreased venous return, it was hypothesized that USVs are the acoustic by-product of the abdominal compression reaction (ACR), a maneuver that increases venous return. If this hypothesis is correct, then other anithypertensive drugs that decrease venous return should evoke USVs. In Experiment 1, sodium nitroprusside (SNP, 400 microg/kg), a direct-acting dilator of arteries and veins, was administered to 15-day-old rats under thermoneutral conditions while cardiac rate and ultrasound production were monitored. In Experiment 2, femoral artery pressure was monitored after SNP administration. Infants responded to SNP administration with decreased arterial pressure and tachycardia and, in addition, significantly increased ultrasound production. In Experiment 3, chlorisondamine (5 mg/kg), a ganglionic blocker that causes vasodilation and bradycardia, and hydralazine (20 mg/kg), a selective dilator of arteries, was administered to 15-day-olds. As predicted, chlorisondamine evoked ultrasound production and hydralazine did not. These results introduce SNP and chlorisondamine as only the second and third known agents capable of independently evoking USVs in thermoneutral conditions, and provide further support for the notion that ultrasound production is triggered by decreased venous return.
Mark S Blumberg; Greta Sokoloff; Robert F Kirby; Tricia G Knoot; Sean J Lewis
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Behavioural brain research     Volume:  131     ISSN:  0166-4328     ISO Abbreviation:  Behav. Brain Res.     Publication Date:  2002 Apr 
Date Detail:
Created Date:  2002-03-07     Completed Date:  2002-05-03     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8004872     Medline TA:  Behav Brain Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  37-46     Citation Subset:  IM    
Program in Behavioral and Cognitive Neuroscience, Department of Psychology, The University of Iowa, E11 Seashore Hall, Iowa City, IA 52242, USA.
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MeSH Terms
Aging / physiology
Antihypertensive Agents / pharmacology*
Blood Pressure / drug effects
Chlorisondamine / pharmacology
Cold Temperature
Ganglionic Blockers / pharmacology
Heart Rate / drug effects
Hemodynamics / drug effects*
Hydralazine / pharmacology
Nitroprusside / pharmacology
Pressoreceptors / drug effects,  physiology
Vasodilator Agents / pharmacology
Vocalization, Animal / drug effects*
Grant Support
Reg. No./Substance:
0/Antihypertensive Agents; 0/Ganglionic Blockers; 0/Vasodilator Agents; 15078-28-1/Nitroprusside; 7701-62-4/Chlorisondamine; 86-54-4/Hydralazine

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