PMID- 1997566
OWN - NLM
STAT- MEDLINE
DCOM- 19910404
LR  - 20190820
IS  - 0022-1422 (Print)
IS  - 0022-1422 (Linking)
VI  - 46
IP  - 2
DP  - 1991 Mar
TI  - Strain differences in baroreflex inhibition by centrally infused enalapril in old 
      rats.
PG  - B65-71
AB  - To determine whether inhibition of the brain renin-angiotensin system would 
      affect baroreflexes similarly in old rats of different strains, we compared 
      24-month-old male Fischer 344 and Sprague-Dawley rats. Baroreflex sensitivity was 
      tested while the rats were awake by recording reflex heart rate responses 
      elicited as blood pressure was elevated with phenylephrine or lowered with sodium 
      nitroprusside. Sprague-Dawley rats had higher blood pressures and lower heart 
      rates initially. Chronic infusion of enalapril, a converting enzyme inhibitor, 
      into a lateral cerebral ventricle (ICV) for two weeks lowered blood pressure in 
      Sprague-Dawley but not in Fischer 344 rats. Furthermore, reflex bradycardia was 
      unaffected in either rat strain, but reflex tachycardia was selectively 
      suppressed in Fischer 344 rats. Thus, although time controls were not done to 
      rule out spontaneous changes during the 14-day infusion period, these results 
      suggest that central cardiovascular regulation does not change similarly with age 
      in these two rat strains. As removal of the brain renin-angiotensin system 
      lowered blood pressure in one strain and inhibited reflex tachycardia in the 
      other, the divergence could mean that the brain renin-angiotensin system acts 
      differently to keep blood pressure elevated in Sprague-Dawley rats and modulate 
      reflex tachycardia in Fischer 344 rats.
FAU - Eriksson, L
AU  - Eriksson L
AD  - Department of Pharmacology, University of Kansas Medical Center.
FAU - Kerecsen, L
AU  - Kerecsen L
FAU - Bunag, R D
AU  - Bunag RD
LA  - eng
GR  - HL-37980/HL/NHLBI NIH HHS/United States
GR  - HL-39383/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Gerontol
JT  - Journal of gerontology
JID - 0374762
RN  - 169D1260KM (Nitroprusside)
RN  - 1WS297W6MV (Phenylephrine)
RN  - 69PN84IO1A (Enalapril)
SB  - IM
MH  - *Aging
MH  - Animals
MH  - Blood Pressure/drug effects
MH  - Bradycardia/chemically induced
MH  - Enalapril/administration & dosage/*pharmacology
MH  - Heart Rate/drug effects
MH  - Infusion Pumps
MH  - Injections, Intraventricular
MH  - Male
MH  - Nitroprusside/pharmacology
MH  - Phenylephrine/pharmacology
MH  - Pressoreceptors/*drug effects
MH  - Rats
MH  - Rats, Inbred F344
MH  - Rats, Inbred Strains
MH  - Reflex/drug effects
MH  - Species Specificity
MH  - Tachycardia/chemically induced
EDAT- 1991/03/01 00:00
MHDA- 1991/03/01 00:01
CRDT- 1991/03/01 00:00
PHST- 1991/03/01 00:00 [pubmed]
PHST- 1991/03/01 00:01 [medline]
PHST- 1991/03/01 00:00 [entrez]
AID - 10.1093/geronj/46.2.b65 [doi]
PST - ppublish
SO  - J Gerontol. 1991 Mar;46(2):B65-71. doi: 10.1093/geronj/46.2.b65.