25453
It is humbling to think that 30 years have passed since the paper by Collingridge , Kehl and McLennan showing that one of Jeff Watkins most interesting compounds , R - 2 - amino - 5 - phosphonopentanoate ( d - AP5 ) , blocked the induction of long - term potentiation in vitro at synapses from area CA3 of the hippocampus to CA1 without apparent effect on baseline synaptic transmission ( Collingridge et al . , 1983 ) .
 Chemical: R - 2 - amino - 5 - phosphonopentanoate; Chemical: d - AP5
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: R - 2 - amino - 5 - phosphonopentanoate; Chemical: d - AP5