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. Author manuscript; available in PMC: 2012 Mar 4.
Published in final edited form as: Cell. 2011 Mar 4;144(5):810–823. doi: 10.1016/j.cell.2011.02.018

Figure 4. MCT1 is induced by training. Disruption of MCT1 expression impairs long-term memory. Memory is rescued by L-lactate.

Figure 4

Mean %, n, latency and detailed statistic are reported in Table S3.

(A) MCTs expression performed on total (T) or synaptoneurosomal (S) extracts of dorsal hippocampus. Postsynaptic density-95 (PSD95) is used to show synaptoneurosmal enrichment. Glial fibrillary acidic protein (GFAP) is used as an astrocytic marker.

(B) Examples and densitometric quantitative western blot analysis of MCT1, MCT2 and MCT4 carried out in dorsal hippocampal extracts from trained and untrained rats (n=6/group) injected with MCT1- or SC1-ODN and euthanized 12 hr after training. MCT1, but not MCT2 or MCT4, was significantly induced by training. This induction was selectively blocked by MCT1-ODN injection. Data are expressed as mean percentage ± SEM of the untrained-SC1-ODN (100%) mean values. All MCTs values were normalized to those of actin.

(C) Examples and densitometric analysis of MCT1, MCT2 and MCT4 quantitative western blots of extracts from dorsal hippocampal punches taken around the needle placement from trained rats that received hippocampal MCT1- or SC1-ODN injections and were euthanized 12 h after training (n=4/group). Data are expressed as mean percentage ± SEM of trained-SC1-ODN (100%) mean values. All MCTs values were normalized to those of actin.

(D-G) Memory acquisition (acq) and retention are expressed as mean latency ± SEM (in seconds, sec).

(D) Hippocampal injections of MCT1-ODN 1 hr before training did not affect short-term memory (n=7/group).

(E) Hippocampal injection of MCT1-ODN disrupted long-term memory. MCT1- or SC1-ODN were injected 1 hr before training and rats were tested 24 hr after training (Test 1) and 6 days later (Test 2). The memory disruption persisted at Test 2, and memory did not recover following a reminder shock (Test 3). MCT1-ODN amnesic rats showed normal retention after re-training (Test 4) (n=10-11/group).

(F) L-lactate but not glucose rescued the memory impairment induced by blocking MCT1 expression (n=7-13/group). MCT1- or SC1-ODN were injected 1 hr before training. Llactate, glucose or vehicle (PBS) were injected 15 min before training. Rats were tested 24 hr after training (Test 1) and 6 days later (Test 2).

(G) High concentration of glucose transiently rescued the MCT1-ODN-induced memory impairment (n = 8-11/group). MCT1- or SC1-ODN were injected 1 hr before training. 150 nmol of glucose or vehicle (PBS) were injected 15 min before training. Rats were tested 24 hr after training (Test 1) and 6 days later (Test 2). * p < 0.05.