Sentence:  These receptors are predominantly diheteromeric GluN1-N2B receptors [8 ,31 ,32 ] whereas those located postsynaptically at the same sites may be largely <WSD>triheteromeric</WSD> GluN1-N2A-N2B receptors [8 ]. 
Meaning of the word marked with <WSD> tags:  Having, or relating to, three different types of subunit