Intramural coronary artery constrictor reactivity to thromboxane is higher in male than in female rats.
BACKGROUND
The prevalence of cardiovascular disorders is higher among men than in age-matched women. This is probably related, in part, to gender-dependent differences in coronary function including thromboxane-A(2) (TXA(2)) sensitivity. This question has been examined only on major, epicardial coronaries. The intramural small arteries directly responsible for supplying the myocardial arterioles with blood have been hardly accessible for investigation, owing to difficulties in their preparation. Vasoconstrictor TXA(2) excess generated by platelets and the vascular wall may play an important role in coronary ischemic events. In the present study we tested the vasoconstrictor reactivity of intramural coronary arteries to TXA(2).


METHODS
Secondary, intramural branches of the left anterior descendent coronary artery of Sprague-Dawley rats (diameter: 200 microm) were placed into a vessel chamber. TXA(2) vasoconstrictor reactivity was measured on the basis of pressure-diameter curves in normal Krebs-Ringer solution and after addition of TXA(2) receptor agonist.


RESULTS
Vasoconstrictor response induced by TXA(2) agonist was twice as strong in males compared with females for the whole pressure range ( p < 0.001).


CONCLUSIONS
A gender-dependent difference was demonstrated in TXA(2)-induced contraction of intramural coronary artery segments. In some pathologic situations the enhanced TXA(2) release from platelets and injured vascular wall may cause greater vasoconstriction of intramural coronary arteries in males than in females.
Varbiro
Szabolcs
S
Second Department of Obstetrics and Gynecology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.
Matrai
Mate
M
Szekeres
Maria
M
Nadasy
Gyorgy L
GL
Szaky
Esther
E
Mericli
Metin
M
Banhidy
Ferenc
F
Monos
Emil
E
Szekacs
Bela
B
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology; D005260:Female; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D044244:Receptors, Thromboxane A2, Prostaglandin H2 / Q000819:agonists*; D012737:Sex Factors; D013928:Thromboxane A2 / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
D044244:Receptors, Thromboxane A2, Prostaglandin H2; D013928:Thromboxane A2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid