Agents that affect cAMP levels or protein kinase A activity modulate memory consolidation when injected into rat hippocampus but not amygdala.

نویسندگان

  • L Bevilaqua
  • P Ardenghi
  • N Schröder
  • E Bromberg
  • J Quevedo
  • P K Schmitz
  • M Bianchin
  • R Walz
  • E Schaeffer
  • J H Medina
  • I Izquierdo
چکیده

Male Wistar rats were trained in one-trial step-down inhibitory avoidance using a 0.4-mA footshock. At various times after training (0, 1.5, 3, 6 and 9 h for the animals implanted into the CA1 region of the hippocampus; 0 and 3 h for those implanted into the amygdala), these animals received microinfusions of SKF38393 (7.5 micrograms/side), SCH23390 (0.5 microgram/side), norepinephrine (0.3 microgram/side), timolol (0.3 microgram/side), 8-OH-DPAT (2.5 micrograms/side), NAN-190 (2.5 micrograms/side), forskolin (0.5 microgram/side), KT5720 (0.5 microgram/side) or 8-Br-cAMP (1.25 micrograms/side). Rats were tested for retention 24 h after training. When given into the hippocampus 0 h post-training, norepinephrine enhanced memory whereas KT5720 was amnestic. When given 1.5 h after training, all treatments were ineffective. When given 3 or 6 h post-training, 8-Br-cAMP, forskolin, SKF38393, norepinephrine and NAN-190 caused memory facilitation, while KT5720, SCH23390, timolol and 8-OH-DPAT caused retrograde amnesia. Again, at 9 h after training, all treatments were ineffective. When given into the amygdala, norepinephrine caused retrograde facilitation at 0 h after training. The other drugs infused into the amygdala did not cause any significant effect. These data suggest that in the hippocampus, but not in the amygdala, a cAMP/protein kinase A pathway is involved in memory consolidation at 3 and 6 h after training, which is regulated by D1, beta, and 5HT1A receptors. This correlates with data on increased post-training cAMP levels and a dual peak of protein kinase A activity and CREB-P levels (at 0 and 3-6 h) in rat hippocampus after training in this task. These results suggest that the hippocampus, but not the amygdala, is involved in long-term storage of step-down inhibitory avoidance in the rat.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

PKMζ contributes in consolidation, retrieval and maintenance of amygdala dependent fear memory in rats

Introduction: Protein kinase M zeta (PKMζ) is assumed to be actively involved in retainig long-term potentiation. The goal of this study was to investigate the role of PKMζ in basolateral amygdala (BLA) upon acquisition, consolidation, retention and retrieval of memory using a specific inhibitor of PKMζ. Methods: Sixty male wistar rats underwent stereotaxic surgery and were cannu...

متن کامل

Early and late consolidation and reconsolidation of memory in the prelimbic cortex

Rats can learn to forage among olfactory cues to associate one with reward in only 3 massed trials. The learning is achieved in less than 10 min and results in a memory trace lasting at least 1wk week. To study the neuro-anatomical circuits involved in the memory formation we used immunoreactivity to the immediate early gene c-fos as a marker for neuronal activity induced by the learning. The p...

متن کامل

Early and late consolidation and reconsolidation of memory in the prelimbic cortex

Rats can learn to forage among olfactory cues to associate one with reward in only 3 massed trials. The learning is achieved in less than 10 min and results in a memory trace lasting at least 1wk week. To study the neuro-anatomical circuits involved in the memory formation we used immunoreactivity to the immediate early gene c-fos as a marker for neuronal activity induced by the learning. The p...

متن کامل

P84: Effect of Insulin-Like Growth Factor 2 (IGF2) as a Microglia-Derived Anti-Iinflammatory Ccytokine on Improving Memory Impairment Following Hippocampal Intracerebral Hemorrhage in Rat

Insulin-like growth factor 2 (IGF2) as a microglia-derived anti-inflammatory cytokine has a pivotal activity in memory consolidation. However, there is limited evidence on brain cell-originated IGF2 expression, regulation and function in pathological condition and neuro-inflammation. Hence, the present study was conducted to investigate the effect of IGF2 on improving the memory impairment in a...

متن کامل

Involvement of hippocampal AMPA glutamate receptor changes and the cAMP/protein kinase A/CREB-P signalling pathway in memory consolidation of an avoidance task in rats.

Training in step-down inhibitory avoidance (0.3-mA footshock) is followed by biochemical changes in rat hippocampus that strongly suggest an involvement of quantitative changes in glutamate AMPA receptors, followed by changes in the dopamine D1 receptor/cAMP/ protein kinase A (PKA)/CREB-P signalling pathway in memory consolidation. AMPA binding to its receptor and levels of the AMPA receptor-sp...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas

دوره 30 8  شماره 

صفحات  -

تاریخ انتشار 1997