Q: Is there a saporin derivative available that selectively destroys all or some hippocampal neurons?
A: Assuming that you mean to eliminate cell bodies from the hippocampus, rather than just projections, a neat paper by Martin et al. describes the use of SSP-SAP (Cat #IT-11) to do this. NPY-SAP (Cat. #IT-28) could also be interesting.
Related: SSP-SAP (Cat. #IT-11), NPY-SAP (Cat. #IT-28)
References