C. Lopezrubalcava, PRESYNAPTIC OR POSTSYNAPTIC ACTIVITY OF 5-HT1A COMPOUNDS IN MICE DEPENDS ON THE ANXIETY PARADIGM, Pharmacology, biochemistry and behavior, 54(4), 1996, pp. 677-686
The purpose of the present study was to compare the contribution of pr
e and postsynaptic 5-HT1A receptors to the anxiolytic effects of serot
onergic(1A) compounds in two animal models of anxiety. To this aim, th
e 5-HT1A ligands buspirone, ipsapirone, indorenate, and 8-OH-DPAT were
tested in the burying behavior test and the avoidance exploratory beh
avior paradigm in control, pCPA-treated, and 5,7-DHT-lesioned mice. p-
CPA and 5,7-DHT treatments did not modify the burying behavior per se,
while 5-HT1A agonists produced a significant reduction in this behavi
or in both p-CPA- and 5,7-DHT-lesioned animals. In the exploratory beh
avior paradigm, p-CPA per se but not 5,7-DHT increased the black/white
transitions, interpreted as an antianxiety action. The ICV injection
of 5,7-DHT blocked such effect of the 5-HT1A compounds in the avoidanc
e exploratory behavior test. Data suggest that the effect of 5-HT1A co
mpounds in the burying behavior test is mediated via the stimulation o
f postsynaptic receptors, while in the avoidance exploratory behavior
paradigm these compounds act through the stimulation of the presynapti
c site. Discussion is based on the differences between the animal mode
ls of anxiety.