Intracerebral injection of polymyxin B blocks the acquisition of conditioned taste aversion in rats.
The contribution of protein kinase C (PKC) to the acquisition of conditioned taste aversion (CTA) was tested by injection of three PKC inhibitors--polymyxin B, H7 and staurosporine--into the parabrachial nucleus (PBN). From the tested drugs only polymyxin B (20 mM) prevented CTA acquisition. Application of H7 (10 mM) and staurosporine (100 and 500 microM) into the PBN did not impair CTA learning. The blocking effect of polymyxin B is dose dependent (5 and 10 mM concentration did not disrupt CTA formation) and site specific (application of polymyxin B into the visual cortex did not elicit CTA blockade). The ability of polymyxin B to disrupt CTA learning is not due to irreversible damage of PBN. These results suggest that polymyxin B blocks acquisition of CTA in some nonspecific way not necessarily involving inhibition of PKC. This conclusion is supported by failure of two other more specific PKC inhibitors to affect CTA learning.
Bielavska
E
E
Institute of Physiology, Academy of Sciences, Praha, Czech Republic.
Krivanek
J
J
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D003216:Conditioning, Operant; D004326:Drinking; D008297:Male; D000077489:Piperazine; D010879:Piperazines / Q000494:pharmacology; D011112:Polymyxin B / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D051381:Rats; D019311:Staurosporine; D013649:Taste; D014793:Visual Cortex
D000470:Alkaloids; D010879:Piperazines; D000077489:Piperazine; D011493:Protein Kinase C; D019311:Staurosporine; D011112:Polymyxin B