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Presence of endothelium prevents contraction induced by phenylephrine (PHE) in aorta from Wistar Audiogenic Rats (WARs) when the sarcoplasmic Ca2+‐ATPase (SERCA) is inhibited.
Author(s) -
Restini Carolina Baraldi,
Oliveira José Antônio Cortes,
Bendhack Lusiane Maria,
GarciaCairasco Norberto
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1163-c
Subject(s) - contraction (grammar) , phenylephrine , medicine , serca , aorta , chemistry , endothelium , endocrinology , endoplasmic reticulum , stimulation , atpase , biophysics , biology , biochemistry , blood pressure , enzyme
Doretto et al, (Behavior Genetics, 33:–42, 2003) developed an audiogenic seizure susceptible strain (WARs). Seizures are often associated to cardiovascular alterations. In order to understand alterations in vascular reactivity in WARs submitted to acoustic stimulation, we have studied Ca 2+ pumping by SERCA and the contraction stimulated with PHE in aorta rings in the absence (E−) and in the presence of endothelium (E+). Startle induced by acoustic pulses was intercalated 24 h between acute and chronic acoustic stimuli, the latter to test audiogenic seizures. Aorta rings were isolated from acoustically stimulated male Wistar and WARs and placed into bath chambers with Krebs Salt Solution (KSS). Contraction induced by 0.3 μM PHE was higher in WARs E− (2.8±0.3g) than in WARs E+ (0.86±0.1g) or in Wistar (E− 1.4±0.02g or E+ 1.6±0.4g). After 10 min in zero‐Ca 2+ , contraction induced by PHE was abolished in aorta from all groups, except in Wistar E− (0.6±0.01g). Ca 2+ addition in presence of PHE did not produce contraction in all groups. Thapsigargin (1μM‐TG) in Ca 2+ ‐free medium did not produce contraction in any group. When Ca 2+ solution was added, in presence of TG, only aorta from Wistar rats contracted (E− 0.5±0.01g; E+ 0.5±0.2g). Contraction induced by PHE in Ca 2+ solution plus TG, did not recover only in WARs E+ (0.3±0.06g). In conclusion, the presence of endothelium prevents the contraction induced by PHE in aorta from acoustically stimulated WARs after SERCA inhibition. Demonstration that this response is endogenous to WARs will be investigated. Support: FAPESP, CNPq, PROAP‐CAPES