You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Brand", "UnapprovedDrug", "Drug", "DrugGroup"].

Please return the output as a JSON object of the format: {"Brand" : ["Aspirin", ...], "DrugGroup": ["Salicyclate", ...], "Drug": ["Phenobarbital", ...], "UnapprovedDrug": ["Heroin", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

In vitro interaction of prostaglandin F2alpha and oxytocin in placental vessels. The interaction of prostaglandin F2alpha and synthetic oxytocin on placental vessels was studied in vitro. Resistance was measured near the placental margin after spontaneous term delivery. In seven experiments reactions to norepinephrine and oxytocin were PGF2alpha. PGF2alpha produced significantly increased vasoconstriction after a single administration of oxytocin. In eight experiments the perfusion medium contained oxytocin. There was no change after a single dose of PGF2alpha. The reaction after norepinephrine remained the same in both groups of experiments. There is thus an enhancement effect There is thus an enhancement effect of PGF2alpha upon the reaction of placental vessels to oxytocin in vitro.
{"Brand": [], "Drug": ["prostaglandin F2alpha", "norepinephrine", "oxytocin", "PGF2alpha"], "DrugGroup": [], "UnapprovedDrug": []}