Histaminergic system of the lateral septum in the modulation of anxiety-like behaviour in rats.
The central histaminergic system is known to have modulatory influence on anxiety-related behaviour both in animals and humans through histamine H1 and/or H2 receptors. In the present study, the effects of intra-lateral septal microinjections of histaminergic agents on anxiety-related behaviours in male Wistar rats have been investigated. As a model of anxiety, the elevated plus-maze which is a useful test to investigate the effects of anxiogenic or anxiolytic drugs in rodents was used. Intra-lateral septal administration of histamine (0.5 and 1 microg/rat) decreased the percentage of open arm entries and open arm time but not locomotor activity, showing an anxiogenic response. The intra-lateral septal injections of different doses of the histamine H1 receptor antagonist, pyrilamine (5, 10 and 20 microg/rat) or the histamine H2 receptor antagonist, ranitidine (5, 10 and 20 microg/rat) could not significantly alter the anxiety-like parameters in the plus-maze test. However, intra-lateral septal injections of different doses of pyrilamine (10 and 20 microg/rat) or ranitidine (10 and 20 microg/rat) significantly reversed histamine (1 microg/rat)-induced anxiogenic effect. The results may indicate that the histaminergic system of lateral septum modulate anxiety-like behaviour through histamine H1 and H2 receptors.
Zarrindast
Mohammad-Reza
MR
Department of Pharmacology and Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran. zarinmr@ams.ac.ir <zarinmr@ams.ac.ir>
Valizadegan
Farhad
F
Rostami
Parvin
P
Rezayof
Ameneh
A
D000818:Animals; D001007:Anxiety / Q000503:physiopathology* / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects; D006632:Histamine / Q000502:physiology*; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008845:Microinjections; D011738:Pyrilamine / Q000008:administration & dosage / Q000494:pharmacology; D011899:Ranitidine / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020665:Septum of Brain / Q000503:physiopathology*; D013238:Stereotaxic Techniques
D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D006632:Histamine; D011899:Ranitidine; D011738:Pyrilamine