RESUMEN
Introduction: The neuronal mechanism driving Alzheimer's disease (AD) is incompletely understood. Methods: Immunohistochemistry, pharmacology, biochemistry, and behavioral testing are employed in two pathological contexts-AD and a transgenic mouse model-to investigate T14, a 14mer peptide, as a key signaling molecule in the neuropathology. Results: T14 increases in AD brains as the disease progresses and is conspicuous in 5XFAD mice, where its immunoreactivity corresponds to that seen in AD: neurons immunoreactive for T14 in proximity to T14-immunoreactive plaques. NBP14 is a cyclized version of T14, which dose-dependently displaces binding of its linear counterpart to alpha-7 nicotinic receptors in AD brains. In 5XFAD mice, intranasal NBP14 for 14 weeks decreases brain amyloid and restores novel object recognition to that in wild-types. Discussion: These findings indicate that the T14 system, for which the signaling pathway is described here, contributes to the neuropathological process and that NBP14 warrants consideration for its therapeutic potential.
RESUMEN
INTRODUCTION: Retrieval (reactivation) of smoking-related memories is a potent trigger of relapse among ex-smokers, and manipulation of smoking-related memories is considered to be a promising target for therapeutic intervention. Recent studies have shown that postreactivation extinction attenuates drug-related memories and relapse to drug-seeking both in rodents and in humans. We investigated the effect of postreactivation extinction in a rat model of relapse to nicotine-seeking. METHODS: Rats were trained to self-administer nicotine in context A (CxA). Pressing the active lever resulted in the nicotine infusion paired with a cue-light (CS). Nicotine-related Pavlovian memories were then reactivated via presentation of 3 non-contingent CS. We then extinguished nicotine-related memories in a distinct context (CxB) followed 24hr later by the assessment of renewal of responding in CxA. RESULTS: Postreactivation extinction, applied 1 but not 6hr after reactivation, induced a significant reduction of the rate of responding on renewal compared to responding during nicotine self-administration, whereas no such effect of CS-Extinction was observed in No-Reactivation group. However, between-group comparisons of responding during renewal did not show any significant difference. CONCLUSIONS: Current results show that the reactivation of nicotine-related Pavlovian memories may reduce the effect of renewal to exert nicotine-seeking. However, it appears that this effect is small in size and is not significantly different from CS-Extinction alone.