Abstract
1. All the barbituric acid derivatives tested cause dilatation of the cerebral vessels.
2. Sodium phenobarbital 50 or 100 mgm. When dissolved in Ringer's solution pH 7.6 modified by the addition of autogenous defibrinated blood to 20 per cent and injected into a perfusate of the same fluid produced marked cerebral vaso-dilatation. If the same quantity of sodium phenobarbital is dissolved in Ringer's solution pH 7.6 and injected into a perfusion fluid of Ringer's pH 7.6 having the same temperature etc., vaso-constriction resulted.
3. The vaso-constriction noted with sodium phenobarbital is due, we believe, to the change in pH of the fluid perfusing through the brain.
4. Fluids with a pH less than the perfusate when injected into it increase the rate of perfusion flow (vaso-dilatation) and fluids with a pH greater than that of the perfusate when similarly injected cause decreased rate of perfusion flow (vaso-constriction).
5. In the brain as in other organs the barbituric acid derivatives act directly upon the vessel wall in producing vaso-dilatation.
6. The beneficial results from the administration of phenobarbital in epilepsy may be in part, due to its cerebral vaso-dilator action.
Footnotes
- Received December 18, 1925.
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