Baclofen does not block interoceptive discriminative stimulus produced by pentylenetetrazol

✍ Scribed by Smart O. Idemudia; Harbans Lal

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 342 KB
• Volume: 14
• Category: Article
• ISSN: 0272-4391
• DOI: 10.1002/ddr.430140108

✦ Synopsis

ldemudia S.O., and H. Lal.: Baclofen does not block interoceptive discriminative stimulus produced by pentylenetetrazol. Drug Dev. Res. 14:85-90, 1988.

Baclofen was compared with diazepam for ability to block the interoceptive discriminative stimulus produced by the anxiogenic drug pentylenetetrazol (PTZ). Male hooded rats of the Long Evans strain were trained in two-lever operant chambers to respond for food reward. Presses on one lever were reinforced after intraperitoneal injections of PTZ (20 mg/kg), and on the other lever after saline. After rats had acquired the PTZ discrimination, it was shown that pretreatment with baclofen failed to block the interoceptive stimulus produced by PTZ, whereas pretreatment with diazepam was effective. As baclofen is ineffective in a conflict procedure as well as in antagonizing the PTZ stimulus, but produces a diazepamlike interoceptive discriminative stimulus, it is concluded that elicitation of the diazepam stimulus may not be related to diazepam's anxiolytic efficacy and that diazepam discrimination may be an inappropriate model for studying anxiolytic properties of drugs. Furthermore, the difference between baclofen and diazepam with respect to anxiolytic efficacy is suggested to be related to receptor specificity. The binding of diazepam facilitates GABAA receptor activity, whereas the binding of baclofen facilitates GABAs receptors. Hence, it is suggested that modulation of GABAA receptors may be critical in diazepam's blockade of the PTZ stimulus.