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Titolo:
CARDIOVASCULAR VARIABILITY AFTER CLONIDINE CHALLENGE - ASSESSMENT OF DOSE-DEPENDENT TEMPORAL EFFECTS BY MEANS OF SPECTRAL-ANALYSIS
Autore:
TULEN JHM; SMEETS FML; INTVELD AJM; VANSTEENIS HG; VANDEWETERING BJM; MOLEMAN P;
Indirizzi:
ERASMUS UNIV ROTTERDAM,HOSP DIJKZIGT,DEPT PSYCHIAT,DR MOLEWATERPLEIN 40 3015 GD ROTTERDAM NETHERLANDS ERASMUS UNIV ROTTERDAM,HOSP DIJKZIGT,PATHOPHYSIOL BEHAV SECT 3015 GD ROTTERDAM NETHERLANDS ERASMUS UNIV ROTTERDAM,HOSP DIJKZIGT,DEPT CLIN NEUROPHYSIOL 3015 GD ROTTERDAM NETHERLANDS ERASMUS UNIV ROTTERDAM,HOSP DIJKZIGT,DEPT INTERNAL MED 1 3015 GD ROTTERDAM NETHERLANDS
Titolo Testata:
Journal of cardiovascular pharmacology
fascicolo: 1, volume: 22, anno: 1993,
pagine: 112 - 119
SICI:
0160-2446(1993)22:1<112:CVACC->2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
HEART-RATE; BLOOD-PRESSURE; ESSENTIAL-HYPERTENSION; ALPHA-ADRENOCEPTORS; HUMANS; OSCILLATIONS; BAROREFLEX; INTERVAL;
Keywords:
CLONIDINE; CARDIOVASCULAR VARIABILITY; HEART RATE; BLOOD PRESSURE; SPECTRAL ANALYSIS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
J.H.M. Tulen et al., "CARDIOVASCULAR VARIABILITY AFTER CLONIDINE CHALLENGE - ASSESSMENT OF DOSE-DEPENDENT TEMPORAL EFFECTS BY MEANS OF SPECTRAL-ANALYSIS", Journal of cardiovascular pharmacology, 22(1), 1993, pp. 112-119

Abstract

Effects of four intravenous (i.v.) doses (0.25, 0.5, 1, and 2 mug/kg)of the alpha2-adrenoceptor agonist clonidine (CLO) were studied in 7 normotensive male volunteers in a placebo-controlled double-blind randomized design to evaluate the role Of alpha2-adrenoceptors in spontaneous short-term cardiovascular fluctuations. Heart rate (HR), systolic and diastolic blood pressure (SBP, DBP; Finapres device), stroke volume (SV) and total peripheral resistance (TPR) were monitored for 1 h after infusion of CLO while the subjects rested in a semirecumbent position. For HR, SBP, and DBP, power spectra and variation coefficients were calculated for consecutive time segments of 2.5 min. Power density was assessed for three frequency bands: low (LFB, 0.02-0.06 Hz), mid (MFB, 0.07-0.14 Hz), and high (HFB, 0.15-0.40 Hz). Per time-segment, baroreflex sensitivity (BRS) was estimated as the gain (or modulus) in MFB between systolic pressure values and R-R interval times. Decreases in mean levels of SBP and DBP were observed within 15 min after infusion of greater-than-or-equal-to 0.5 mug/kg CLO. HR first showed a slight increase 15 min after infusion of 0.5, 1, and 2 mug/kg CLO, but decreased subsequently as in all doses, including placebo. SV and TPR decreased after a dose of 2 mug/kg CLO. LFB and MFB power of HR were reduced after 2 mug/kg CLO, but only during the first 30 min after infusion; during this period, respiratory depth was also diminished, indicating that these effects may reflect a reduction in sympathetic outflow aswell as a reduction in vagal outflow. Respiratory frequency did not change after CLO, nor did BRS. DBP MFB power was reduced after 2 mug/kgCLO during the entire postinfusion period, probably as a reflection of reduced sympathetic outflow. SBP HFB power was significantly increased after greater-than-or-equal-to 0.5 mug/kg CLO, but only after 30 min of infusion, which could be a consequence of alterations in both vagal outflow and mechanical respiratory properties. Thus, in a dose range of 0.25-2 mug/kg CLO, significant effects were detected for SBP, DBP, and HR after greater-than-or-equal-to 0.5 mug/kg, whereas spontaneous short-term fluctuations of HR and DBP were influenced only after a dose of 2 mug/kg. The effects were slight but could be detected within a postinfusion period of 1 h. Our data show that sequential spectral analysis of spontaneous hemodynamic fluctuations can be used to unraveltime-dependent dynamics of sympathetic and vagal components in short-term cardiovascular control.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 05:32:09