The effects of histaminergic agents in the central amygdala of rats in the elevated plus-maze test of anxiety.
Behav Pharmacol
; 16(8): 643-9, 2005 Dec.
Article
en En
| MEDLINE
| ID: mdl-16286816
ABSTRACT
Reports indicate that histamine and histaminergic agents can change anxiety-related behaviours in both animals and humans. The amygdala is an important brain site in the modulation of fear or anxiety. In the present study, we investigated the effects of intracentral amygdala microinjection of histaminergic agents on anxiety-related behaviours in rats, using the elevated plus-maze test of anxiety. Intracentral amygdala administration of histamine (0.01-0.5 microg/0.5 microl bilateral) decreased %open armtime and % open arm entries, but not locomotor activity, showing an anxiogenic response. Intracentral amygdala microinjection of pyrilamine (H1 receptor antagonist) and ranitidine (H2 receptor antagonist) (both at 1-20 microg/0.5 microl bilateral) did not change anxiety-related parameters in our experiments. In another series of experiments, histamine (0.5 microg/0.5 microl bilateral) was coadministrated with pyrilamine and ranitidine (both at 1-20 mg/0.5 microl bilateral). The results showed that pyrilamine but not ranitidine could significantly reverse the anxiogenic effect of histamine at doses of 10 and 20 microg/0.5 microl bilateral. The results suggest that histamine may modulate anxiety via H1 but not H2 receptors in the rat central amygdala.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ansiedad
/
Histamínicos
/
Amígdala del Cerebelo
Límite:
Animals
Idioma:
En
Revista:
Behav Pharmacol
Asunto de la revista:
CIENCIAS DO COMPORTAMENTO
/
FARMACOLOGIA
Año:
2005
Tipo del documento:
Article
País de afiliación:
Irán