Effects of in ovo and acute diazepam treatments on peripheral benzodiazepine receptors and cutaneous basophil hypersensitivity in chickens.
Prenatal diazepam treatment impairs immune responses in mammals, but chicken embryos allow experimental manipulation isolated from maternal influences on embryo development. In ovodiazepam treatment in chickens decreased macrophage spreading and phagocytosis. In the present experiment, we investigated the effects of in ovoand/or acute diazepam treatments on phytohemagglutinin (PHA)-induced cutaneous basophil hypersensitivity (CBH) response in chickens. Forty day-old chickens, treated in ovo with 8 mg diazepam/kg, 2 ml diazepam vehicle/kg, or sham-manipulated. were subsequently treated po with 2 mg diazepam/kg or with diazepam's vehicle 1 h before PHA injection. The existence of an interaction between diazepam treatments was shown. Birds acutely treated with diazepam exhibited an increment in CBH response. In contrast, in ovo diazepam treatment per se did no change animals' response to PHA, but antagonized acute diazepam effects on CBH response. The results occurred through direct and/or indirect action of diazepam on cytokine and/or glucocorticoid hormone production and release. In the former case, the effects might be related to stimulation of peripheral benzodiazepine receptors (PBR) on immune cells, thus changing the cytokine cascade, while in the latter instance they might be mediated through glucocorticoid hormones via PBR stimulation in the adrenal gland cells.
Morgulis
Maria Sílvia F A
MS
Applied Pharmacology and Toxicology Laboratory, Department of Pathology School of Veterinary Medicine, University of São Paulo, Av Prof Dr Orlando Marques de Paiva, 87 CEP 05508-900, São Paulo, Brazil.
Palermo-Neto
João
J
D000818:Animals; D014151:Anti-Anxiety Agents / Q000633:toxicity*; D001491:Basophils / Q000187:drug effects* / Q000276:immunology; D002642:Chick Embryo; D002645:Chickens; D003975:Diazepam / Q000633:toxicity*; D005260:Female; D006967:Hypersensitivity / Q000276:immunology; D010835:Phytohemagglutinins / Q000187:drug effects* / Q000276:immunology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011963:Receptors, GABA-A / Q000187:drug effects*
D014151:Anti-Anxiety Agents; D010835:Phytohemagglutinins; D011963:Receptors, GABA-A; D003975:Diazepam