execute a cypher ":param" statement?

[paul-shannon]

Having just learned how to set a variable in cypher, I hope now to do the same via neo4r, rather than programmatically building a large string in R.

In cypher:

:param reactions => ['R_HMR_4283', 'R_HMR_4372'];   # imagine this is 50 elements long
match(m1:Metabolite)-[:substrateOf]->(r:Reaction)-[:produces]->(m2:Metabolite) 
   where r.id IN $reactions return m1,r,m2;

Is it possible to execute the :param statement from R using neo4r?
Thank you.