On vasodilators, magnesium and second messengers.
Detailed hemodynamic studies of vasodilating compounds in anesthetized dogs were performed. Multichannel electromagnetic flowmetry at organ level showed for a number of peptide hormones and biogenic amines that each chemical entity had its own "map" of vascular responses. In contrast magnesium-ions appear to reduce vascular resistance in each vascular area, in a similar time-frame, similar dose-dependency and without changing left ventricular volume output or perfusion of any vascular bed. The restricted vascular activity of the hormones and amines is set against the homogeneity of the morphology of arteriolar walls throughout the body. The hypothesis is put forward that these compounds cause vasodilation through release of one or more metabolites from their target cells. Such a metabolite would then act as a second messenger. A number of requirements are set forth for reactions to be expected after intravenous administration of such a hypothetical metabolite. It is concluded that magnesium and may be potassium fulfill these requirements, and should therefore be considered as potential second messenger vasodilators.
D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001775:Blood Circulation / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D005934:Glucagon / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects*; D008274:Magnesium / Q000494:pharmacology / Q000502:physiology*; D015636:Magnesium Chloride; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010418:Pentagastrin / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D012212:Rheology; D012633:Secretin / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D015636:Magnesium Chloride; D012633:Secretin; D014660:Vasoactive Intestinal Peptide; D001262:Atenolol; D005934:Glucagon; D010418:Pentagastrin; D008274:Magnesium; D011188:Potassium; D009638:Norepinephrine