In:
European Journal of Neuroscience, Wiley, Vol. 14, No. 9 ( 2001-11), p. 1522-1532
Kurzfassung:
We investigated the effects of agents acting at histamine receptors on both, spontaneous release of ACh from the basolateral amygdala (BLA) of freely moving rats, and fear conditioning. Extensive evidence suggests that the effects of histamine on cognition might be explained by the modulation of cholinergic systems. Using the microdialysis technique in freely moving rats, we demonstrated that perfusion of the BLA with histaminergic compounds modulates the spontaneous release of ACh. The addition of 100 m m KCl to the perfusion medium strongly stimulated ACh release, whereas, 0.5 µ m tetrodotoxin (TTX) inhibited spontaneous ACh release by more than 50%. Histaminergic H 3 antagonists (ciproxifan, clobenpropit and thioperamide), directly administered to the BLA, decreased ACh spontaneous release, an effect fully antagonized by the simultaneous perfusion of the BLA with cimetidine, an H 2 antagonist. Local administration of cimetidine alone increased ACh spontaneous release slightly, but significantly. Conversely, the administration of H 1 antagonists failed to alter ACh spontaneous release. Rats receiving intra‐BLA, bilateral injections of the H 3 antagonists at doses similar to those inhibiting ACh spontaneous release, immediately after contextual fear conditioning, showed memory consolidation impairment of contextual fear conditioning. Post‐training, bilateral injections of 50 µg scopolamine also had an adverse effect on memory retention. These observations provide the first evidence that histamine receptors are involved in the modulation of cholinergic tone in the amygdala and in the consolidation of fear conditioning.
Materialart:
Online-Ressource
ISSN:
0953-816X
,
1460-9568
DOI:
10.1046/j.0953-816x.2001.01780.x
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
2001
ZDB Id:
2005178-5
SSG:
12
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