Angiotensin IV enhances LTP in rat dentate gyrus in vivo.

摘要: Abstract Angiotensins have been shown to play a significant role in variety of physiological functions including learning and memory processes. Relatively recent evidence supports the increasing importance angiotensin IV (Ang IV), many these previously associated only with Ang II, memory. An interesting hypothesis generated by results has that II is precursor for production more active peptide fragment, IV. Since impairs memory, when administered directly or released into hippocampal dentate gyrus, inhibits long term potentiation (LTP) medial perforant path-dentate granule cell synapses, as well; it remained be seen what effects had on LTP same synapses. Results this study show clearly significantly enhances LTP, enhancement both dose time dependent. The following solutions were over five min period, at end baseline before first tetanus was applied: 2.39, 4.78, 9.56 nM. inverted U-type related effect observed. A complex observed maximum 5 min, return normal 30 minimum below 90 120 min. 4.78 nM solution determined intervals between administration tetanus: 5, 15, 30, 60, 90, can prevented pretreatment Divalinal, an antagonist, without any LTP. Two Divalinal used; μM, μM effective completely blocked also obtained Nle 1 -Ang (Norleucine), agonist. Norleucine less than displayed similar course activity. Both produced suppression min; remains explained. However, inhibition dependent Divalinal. fact losartan, AT receptor puzzling since no II.