RESUMEN
Objective. To evaluate the possible migration of polymethylmethacrylate after injections in various corporal compartments of Wistar rats. Methods. The experimental work consisted in the injection of PMMA in corporal compartments for later histopathological analysis of the locations of implants and of distant filtering organs. The dose applied in each implant was of 0.2 mL. The animals were divided into groups according to the location of the implant realized: group GB had intradermic injections in the glabella. Group SD had subdermal injections in dorsal subcutaneous tissue cells. Group IP had intraperitoneal injections in the abdomen. Group PD had intramuscular injections in the right rear leg. The rats were sacrificed 30 days after realization of the implants and tissue samples from the lung, liver, spleen, and kidney, and locations of implantation were removed for histopathological analysis. Results. Characteristic microspheres that were compatible with the presence of PMMA in any of the histological slides analyzed were not observed. One animal had an amorphous exogenous substance, with a histiocytic reaction. Twelve of the 16 lungs analyzed had locations of intraalveolar hemorrhaging. Two animals had nonspecific spleen alterations. Conclusion. The histopathological analysis of this study found no PMMA microspheres in any of the tissues analyzed.
RESUMEN
The effects of systemic injections of the 5HT(1A) receptor agonist 8-OH-DPAT on the spontaneous ingestive, maintenance, locomotor and sleep-like behaviours, and the sleep/waking-related hippocampal electrographic activity were investigated in pigeons. 8-OH-DPAT (0.06, 0.2, 0.6 or 2.0mg/kg) was found to dose-dependently reduce food and water intake, acutely (in the first 3h) and 24h after treatment, during both low-activity morning hours (starting at 10:00 h) and high-activity evening hours (starting at 14:00 h). Automated 24h records of food and water intake indicated that hypophagic effects can last up to 18 h after injection. Duration and incidence of sleep-like postures increased at all doses, in both morning and afternoon. These effects were associated with decreases in exploratory and preening activities. The 8-OH-DPAT-induced hypnogenic, hypophagic and hypodipsic effects tended to be more intense in the morning than in the afternoon-trials. Pretreatment with WAY 100635 (a 5-HT(1A) antagonist; 0.6 mg/kg) eliminated all of these 8-OH-DPAT-induced effects. WAY 100635 failed to affect feeding when injected alone, but decreased frequency of sleep-like responses and increased the latency to the first sleep-like episode. Hippocampal EEG tracings after 8-OH-DPAT injections (0.6 or 2.0mg/kg) indicated that the hypnogenic effects are associated with a specific increase in the frequency and duration of slow wave sleep. Power density analysis of the hippocampal EEG failed to show differences between 8-OH-DPAT-induced sleep and the sleep occurring after vehicle injections, indicating that it may be electrographically similar to diurnal sleep episodes in the pigeon. These data suggest that while 5-HT(1a) receptor-mediated mechanisms play crucial roles in ingestive and sleep/waking behaviours in mammals and birds, their action upon these states shows substantial inter-taxon variance.