Anxiolytic effects of serotonergic interventions in the shock-probe burying test and the elevated plus-maze test.
Although serotonergic neural systems have been implicated in the control of anxiety for a number of years, evidence in favour of this role is controversial. The present experiments were designed to further characterize the putative role of serotonin (5-HT) in anxiety, using two pharmacologically validated animal models: the elevated plus-maze and the shock-probe burying tests. If the integrity of 5-HT neural systems is necessary for the expression of 'anxious' behaviors, then disruption of 5-HT systems should produce effects in the plus-maze and shock-probe tests that are similar to those of anxiolytic drugs. In the present experiments, serotonergic function was disrupted in rats, either by chemical depletion using the synthesis inhibitor p-CPA, by inhibitory autoreceptor activation using the selective 5-HT1A receptor ligand 8-OH-DPAT, or by electrolytic lesions of the serotonin-containing, dorsal raphe nucleus. p-CPA and dorsal raphe lesions produced robust anxiolytic effects in the elevated plus-maze and the shock-probe burying tests, whereas 8-OH-DPAT produced anxiolytic effects only in the shock-probe burying test, and 'anxiogenic' effects in the elevated plus-maze test. Although these results generally support the view that serotonin plays a role in the expression of 'anxious' behavior, the opposite effects of 8-OH-DPAT in the two behavioral paradigms suggest that the 5-HT1A receptor subtype exerts differential control over different types of experimental anxiety.
Department of Psychology, University of Alberta, Edmonton, Canada.
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Treit
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Robinson
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Rotzinger
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Pesold
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D001143:Arousal / Q000187:drug effects / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D001931:Brain Mapping; D004193:Discrimination Learning / Q000187:drug effects / Q000502:physiology*; D004924:Escape Reaction / Q000187:drug effects / Q000502:physiology*; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D010134:Fenclonine / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009949:Orientation / Q000187:drug effects / Q000502:physiology*; D011903:Raphe Nuclei / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000502:physiology*
D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D010134:Fenclonine