Genetic influences on cardiovascular responses to an acoustic startle stimulus in rats
Clin Exp Pharmacol Physiol. 2001-12-06; 28(12): 1096-1099
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1. Clin Exp Pharmacol Physiol. 2001 Dec;28(12):1096-9.
Genetic influences on cardiovascular responses to an acoustic startle stimulus in
Baudrie V(1), Laude D, Chaouloff F, Elghozi JL.
(1)INSERM E0107, Centre de Pharmacologie Clinique de l’Association Claude
Bernard, Hôpital Necker, Paris, France.
1. The aim of the present study was to assess the cardiovascular differences
among five inbred rat strains (n=16 per strain), including spontaneously
hypertensive rats (SHR), Wistar Kyoto (WKY) rats, Wistar Furth (WF) rats, Fischer
(F344) rats and Lewis (Lew) rats and the usual outbred Wistar (W) rat strain
(n=25). 2. These strains were compared under resting conditions for blood
pressure (BP) and heart rate (HR) levels and for their baroreceptor-HR reflex
sensitivity. In addition, their responses to an acoustic startle stimulus were
measured. 3. A consistent rise in BP was observed among the groups as a result of
the noise stimulus. This rise in systolic BP (SBP) averaged (+/-SEM) 37 +/- 2
mmHg in the SHR and 34 +/- 4 mmHg in F344 rats, while the response was only 23
+/- 3 mmHg in WKY rats. Pulse pressure (PP) was increased following noise in all
groups. The delay for the BP response for all groups combined was 1.6 +/- 0.1 s.
4. Most animals had minimal HR variations, except F344 rats, responding with a 42
+/- 13 b.p.m. decrease 3.0 s after the stimulus (i.e. 1.3 s after the maximal 34
+/- 4 mmHg SBP rise). 5. The highest SBP (160 +/- 3 mmHg) and diastolic BP (104
+/- 3 mmHg) were observed in inbred SHR. Other groups were normotensive. Resting
PP was elevated for SHR (56 +/- 2 mmHg) compared with the other groups (40 +/- 2
mmHg). The highest HR was found in F344 and WF rats, with 389 +/- 11 and 372 +/-
7 b.p.m., respectively. The lowest HR was observed in SHR and Lewis rats, with
335 +/- 7 and 323 +/- 7 b.p.m., respectively. The least sensitive baroreflex
function was observed in SHR (0.8 +/- 0.1 b.p.m./mmHg) compared with the other
strains (1.4 +/- 0.2 b.p.m./mmHg). 6. The present study confirms the importance
of genetic factors on the cardiovascular responses of rats to a noise startle
stimulus. Two inbred normotensive rat strains, namely F344 and WKY rats, which
exhibit a substantial difference in pressor response to noise, may be used to
unravel the mechanisms of sympathetic activation.
PMID: 11903324 [Indexed for MEDLINE]