Figure 8.

Acute or prolonged feeding stimulation does not alter tyrosine phosphorylation or protein expression levels of NR2A and NR2B NMDA-R subunits immunoprecipitated in LHA-containing tissue. Immunoprecipitated NR2A (A) and NR2B (B) subunits from 48 hr-food-deprived rats (Fasted) and their ad libitum-fed controls (Fed) were probed with antibodies directed against either phosphotyrosine (pTyr) or the subunits themselves (NR2A or NR2B). Lanes marked Ab were loaded with only Protein A/G and were still reacted with antibodies to assess background staining. Lanes marked Preimmune were loaded with naive hippocampal homogenates immunoprecipitated only with preimmune serum. Each Fed or Fasted band includes bilateral LHA-containing homogenized tissue from two rats (4 tissue micropunches), although, in some instances, at least three animals were used. Data are representative of two experiments, each using 9 or 10 rats per feeding condition; total n = 38 rats. C, Mean levels ± SEM in OD units of tyrosine phosphorylation (top graph) and protein expression (bottom graph), respectively, for the NR2A and NR2B subunits immunoprecipitated in A and B. Mean scores were obtained using all data from both experimental runs (for details, see Materials and Methods). IP, Immunoprecipitated protein; IB, immunoblotted protein; pTyr, phosphotyrosine immunostaining.