Angiotensin II blocks hippocampal long-term potentiation.
We have found that injection of angiotensin II (AII) above the hippocampus in the intact rat blocks the induction of long-term potentiation (LTP) in perforant path-stimulated dentate granule cells. A minimum dose of 4.78 pmol AII was required for the complete blockade of LTP and this blockade was entirely prevented if the AII-specific antagonist saralasin was co-injected at a 50-fold molar excess. AII thus appears to act via AII receptors and does not cause non-specific inhibition. The injection of saralasin alone yielded LTP comparable to that obtained when vehicle was injected. Angiotensin III was found to be 40-50 fold less potent than AII in blocking LTP. Both AII and AII receptors of unknown function occur in the hippocampal formation. The results reported here suggest a role for these molecules in the control of hippocampal LTP.
Denny
J B
JB
Division of Life Sciences, University of Texas, San Antonio 78249.
Polan-Curtain
J
J
Wayner
M J
MJ
Armstrong
D L
DL
D000595:Amino Acid Sequence; D000804:Angiotensin II / Q000378:metabolism / Q000494:pharmacology*; D000805:Angiotensin III / Q000494:pharmacology; D000818:Animals; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D051381:Rats; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000378:metabolism; D012504:Saralasin / Q000494:pharmacology
D011945:Receptors, Angiotensin; D000804:Angiotensin II; D000805:Angiotensin III; D012504:Saralasin