TUBA (or "similar to dynamin binding protein") is a novel scaffold protein recently found to be significantly reduced in neuropathologically-confirmed Alzheimer disease brains. It is highly concentrated at synapses and interacts with dynamin to regulate the actin cytoskeleton and the dynamics of the synaptic vesicle pools. Aim of the present study was to verify whether this protein plays a role in age-related decline of long-term memory performance in rats. TUBA expression was quantified by means of quantitative reverse transcription polymerase chain reaction (qRT-PCR) in the hippocampi of aged (26-27 month old) female Wistar rats which underwent a single trial step-through inhibitory avoidance test. The behavioural paradigm consisted of a training test in which animals were placed individually in the light compartment of a shock avoidance apparatus and were trained to avoid the dark compartment of the conditioned chamber by the delivery of a single 0.6 mA, 2 s inescapable foot shock when they accessed it. Rats were tested for long-term memory 3 and 6 hours after the training. According to the performance displayed in the tests, animals were divided into two groups: i) good responders (GR), which obtained retention times above 100s in both tests, and ii) bad responders (BR), which obtained retention times below 100s in both tests. Six hours after the training, hippocampi were excised and total RNA was extracted. beta-glucuronidase mRNA expression levels were used as normalization standard. mRNA levels of the scaffold protein TUBA were analysed using qRT-PCR. The expression levels of TUBA mRNA were significantly higher in GR than in BR rats (fold change=1.46; p=0.007). Present results suggest that low levels of TUBA in the hippocampus could contribute to the impairment of long-term memory in BR animals, likely inducing alterations of the hippocampal synaptic function.
real time PCR