[Physiopathology and treatment of vascular spasms]

Vasomotricity and tonus of arterial and arteriolar vessels yield to nervous regulation (central and peripheral, hormonal, metabolic) as well as to local myogenic regulation. The main mediators of vasomotricity are catecholamines which, by their alpha and beta effects, have an effect on the second mediator (3'5' AMP) and on calcic exchanges, angiotension, serotonin and prostaglandins which "modulate" vasomotor reactions. Metabolic factors: pH, PO2, PCO2 and electrolytes balance: Na, K, Mg, Ca have to be considered. The role of the metabolism of the wall and the role of red blood corpuscles (ADP) and of platelets (released substances of granules) have to be mentioned. The physiopathology of spasm must take into account topographic variations. One can distinguish spasms by nervous regulation, by catecholamines discharge and by extreme and lasting muscular contraction. Medicines of the spasm can have an effect on the peripheral sympathetic nervous system, catecholamines, the 3'5' AMP and especially on the smooth muscular fibre, more accessorily on red blood corpuscles, platelets and coagulation. Na nitroprussiate and calcium chelating agents are the most active substances to-day.