title: Subtypes of substance P receptor immunoreactive interneurons in the rat basolateral amygdala.
abstract: Local injections of the neurotoxin SP-saporin into the basolateral amygdala (BLA) are reported to specifically lesion substance P receptor immunoreactive (SPR-IR) interneurons, and to reduce anxiety related behavior. Hence, this technique might provide a means to study how defined interneuron populations regulate neuronal activity in the BLA. However, what interneuron subgroups in the BLA might be targeted by SP-saporin lesions has not been established. This study has used dual-labeling immunofluorescence in the rat BLA to examine SPR-IR neurons for their colocalization with the calcium-binding proteins; calbindin-D28k (CB), parvalbumin (PV), and calretinin (CR); and the neuropeptides somatostatin (SOM) and neuropeptide Y (NPY). We found that all NPY-IR neurons and 45% of SOM-IR interneurons expressed SPR-IR, and that 50% and 51% of the SPR-IR interneuron population expressed NPY- and SOM-IR, respectively. Previous studies have reported that approximately a third of SOM-IR interneurons also express NPY, which suggests a large degree of overlap between the NPY, SOM and SPR expressing neurons in the BLA. We also found that the majority of SPR-IR cells were CB-IR (62%), but that these interneurons represented only 2.8% of the total CB-IR population. Moreover, SPR-IR interneurons did not express either PV-or CR- IR. Hence, SP-saporin lesions would ablate all interneurons in the BLA that contain NPY, but leave the majority of the CB-IR cells intact, and have no effect on the CR- and PV-IR populations. Consequently, these results support the use of SP-saporin lesions as a useful technique to study the role of NPY-IR interneurons in the BLA.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University, Woodruff Memorial Building, 1639 Pierce Drive, Rm. 4000, Atlanta, GA 30322, USA. llevita@emory.edu
authors.forename: Liat
authors.initials: L
authors.lastname: Levita
authors.forename: Irakli
authors.initials: I
authors.lastname: Mania
authors.forename: Donald Gordon
authors.initials: DG
authors.lastname: Rainnie
mesh_terms: D000679:Amygdala / Q000166:cytology*; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002452:Cell Count; D007150:Immunohistochemistry; D007395:Interneurons / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018040:Receptors, Neurokinin-1 / Q000145:classification / Q000378:metabolism*; D013004:Somatostatin / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D009478:Neuropeptide Y; D018040:Receptors, Neurokinin-1; D013004:Somatostatin