Self-regulation of ICSS duration: effects of anxiogenic substances, benzodiazepine antagonists and antidepressants.
A variety of anxiogenic substances, benzodiazepine antagonists and antidepressants were tested in a shuttlebox task in which rats interrupted infrared beams to initiate (ON latency) and terminate (OFF latency) continuous rewarding brain stimulation. It was hypothesized that substances exhibiting anxiogenic activity in animals (pentylenetetrazol and beta-CCM) would selectively reduce the OFF latency, since anxiolytic drugs increase this latency. beta-CCM, however, did not alter the OFF latency, but instead lengthened the ON latency. Pentylenetetrazol showed a similar, though not significant, trend. Ro 15-1788 did not alter ON latencies, but selectively lengthened the OFF latency at a high dose, consistent with previously reported anxiolytic activity at such doses. In contrast, CGS 8216 lengthened the ON latency selectively. Thus, Ro 15-1788 was differentiated from other drugs that antagonize benzodiazepines. Caffeine and dopamine uptake-blocking antidepressants (amineptine and nomifensine) preferentially decreased ON latencies, while non-dopamine-blocking antidepressants (viloxazine and CGS 7525A) lengthened both latencies nonspecifically. In conclusion, the OFF latency (but not the ON latency) appears refractory to reduction by various classes of psychotropic agents.
Gerhardt
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Liebman
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D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D014151:Anti-Anxiety Agents / Q000037:antagonists & inhibitors*; D000928:Antidepressive Agents / Q000494:pharmacology*; D001007:Anxiety / Q000139:chemically induced*; D001570:Benzodiazepinones / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology; D002243:Carbolines / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects; D003292:Convulsants / Q000494:pharmacology; D005442:Flumazenil; D006801:Humans; D008297:Male; D010433:Pentylenetetrazole / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D012653:Self Stimulation / Q000187:drug effects*; D013997:Time Factors
D000317:Adrenergic alpha-Antagonists; D014151:Anti-Anxiety Agents; D000928:Antidepressive Agents; D001570:Benzodiazepinones; D002243:Carbolines; D003292:Convulsants; D011720:Pyrazoles; D002110:Caffeine; D005442:Flumazenil; C033830:2-phenylpyrazolo(4,3-c)quinolin-3(5H)-one; C036150:beta-carboline-3-carboxylic acid methyl ester; D010433:Pentylenetetrazole