Effect of pentylenetetrazol on the carbaryl-induced changes of serotonin metabolism in rat-brain hypothalamus.
Carbaryl (200 mg/kg or 400 mg/kg, p.o.) significantly elevated serotonin (5-HT) (57-109%) and 5-hydroxyindoleacetic acid (5-HIAA) (60-78%) levels at 1.0 h in the hypothalamic region of adult male rat brain. Further, administration of carbaryl (200 mg/kg, p.o.) for different time intervals (0.5 h, 1.0 h, and 2.0 h) revealed that both 5-HT and 5-HIAA levels elevated maximally at 0.5 h in hypothalamus. These regional 5-HT and 5-HIAA levels were not significantly affected with pentylenetetrazol (PTZ) at any time after its treatment. But simultaneous administration of carbaryl (200 mg/kg, p.o.) and PTZ (60 mg/kg, s.c.) reduced the carbaryl-induced elevation of both 5-HT and 5-HIAA levels. Measurement of (i) probenecid-induced (200 mg/kg, i.p.) accumulation and (ii) pargyline-induced (75 mg/kg, i.p.) depletion of hypothalamic 5-HIAA level in the absence or presence of carbaryl (200 mg/kg, p.o.) and/or PTZ (60 mg/kg, s.c.) revealed that (a) carbaryl enhanced the synthesis as well as the breakdown of 5-HT, (b) PTZ had no effect on either of these processes of 5-HT, and (c) carbaryl-induced increased catabolism of 5-HT became normal in the presence of PTZ.
D000818:Animals; D012721:Carbaryl / Q000494:pharmacology*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010293:Pargyline / Q000494:pharmacology; D010433:Pentylenetetrazole / Q000494:pharmacology*; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000378:metabolism*
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D010293:Pargyline; D011339:Probenecid; D012721:Carbaryl; D010433:Pentylenetetrazole