Coronary reflex

Coronary reflex is the change of coronary diameter in response to chemical, neurological or mechanical stimulation of the coronary arteries.

The coronary reflexes are stimulated differently from the rest of the vascular system.

Causes of coronary constriction

Chemical
  • N-nitro L-arginine
  • indomethacin
  • glibenclamide
  • tetraethylammonium chloride
  • caffeine

Other
  • Cold

Causes of coronary dilation

Cocaine abuse frequently can cause a coronary spasm, resulting in a spontaneous myocardial infarction.

Chemical
  • Versed (Midazolam): a coronary dilator. In midazolam's presence, dilation was unaffected by N-nitro L-arginine, indomethacin and glibenclamide.
  • Tetraethylammonium chloride, an inhibitor of the BKCa K+ channel (a high conductance Ca2+-sensitive K+ channel), dose dependently attenuated the vasodilating effect of midazolam [1]
  • Estrogen has been shown to abolish abnormal cold-induced coronary constriction.[2]
gollark: They might be. You're only seeing the best/most important people around on Earth, who are more likely than average to have bloodlines.
gollark: It would be interesting to know exactly why the "system" is way more concerned with human-recognizable things than our laws of physics, and also why basically everyone is humanlike mentally despite entirely different evolutionary paths. Unfortunately, all the fictional things I know in this sort of setting just handwave it.
gollark: Ideally, pylon-of-civilization-hunting von Neumann machines, but those might not be practical yet.
gollark: The obvious solution to this """voting"" is to send really fast people out to gather all pylons of civilization and move them to a central base.
gollark: Yes. This is a good idea. I don't like it.

References
  1. O.L. Woodman; G.J. Dusting (1991). "N-nitro L-arginine causes coronary vasoconstriction and inhibits endothelium-dependent vasodilatation in anaesthetized greyhounds". Br. J. Pharmacol. 103 (2): 1407–1410. doi:10.1111/j.1476-5381.1991.tb09802.x. PMC 1908370. PMID 1909199.
  2. Steven E. Reis, MD; Richard Holubkov; Kathleen A. Zell, BSN; AJ. Conrad Smith, MD; Howard A. Cohen, MD; Marc D. Feldman, MD; Roger S. Blumenthal, MD (1998). "Estrogen Acutely Abolishes Abnormal Cold-Induced Coronary Constriction in Men*". Chest. 114 (6): 1556–1561. doi:10.1378/chest.114.6.1556. PMID 9872188.
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