Anatomic study of the arterial vascularization of the brain base of paca (Cuniculus paca) / Estudo anatômico da vascularização arterial da base do encéfalo da paca (Cuniculus paca)

Paca (Cuniculus paca Linnaeus, 1766), rodent belong to the Cuniculidae family, has encouraged numerous scientific researches and for this reason could be an experimental model in both human and veterinary areas. And recently, the economic exploitation of the meat cuts, has being direct implication in its zootechnical importance. However, no anatomical descriptions regarding the vascularization of the base of the brain in this rodent has being found. Thus, the aim of the present study was to describe the arteries and the pattern of the vasculature and to compare it with the other species already established in the literature. For this, five pacas, donated by the Unesp Jaboticabal Wildlife Sector, were euthanized followed by the vascular arterial system was injected with red-stained-centrifuged latex by the common carotid artery. After craniectomy, the brains were removed and the arteries were identified and, in addition, compared with those described in other animal species. The presence of the right and left vertebral arteries, close to the medulla oblongata, was detected, originating the basilar artery, which divided into the terminal branches of the right and left basilar artery. Ventral to the optic tract there was the right internal carotid artery and the left, dividing the middle cerebral artery and left rostral and right; dorsal to the optic chiasm, the medial branch of the rostral cerebral arteries was identified. Based on the results, it is concluded that the vascularization of the paca brain base is supplied by the carotid and vertebrobasilar system.(AU)

A paca (Cuniculus paca Linnaeus 1766), roedor da família Cuniculidae, tem encorajado inúmeras pesquisas científicas, tornando-a modelo experimental tanto na área humana quanto na veterinária, além da recente exploração econômica de seus cortes cárneos, que favoreceu diretamente sua importância zootécnica. No entanto, não há até o momento, descrições anatômicas referentes à padronização da vascularização da base do encéfalo neste roedor. Assim, o objetivo do presente trabalho foi realizar tal delineamento arterial nessa região do sistema nervoso central e compará-lo com as demais espécies já estabelecidas na literatura. Para isso, foram eutanasiadas cinco pacas doadas pelo setor de Animais Silvestres da Unesp Jaboticabal, as quais foram submetidas posteriormente à injeção de látex centrifugado e corante líquido xadrez vermelho, pela artéria carótida comum. Após craniectomia e segregação do encéfalo de todos os cadáveres, realizou-se a identificação das artérias presentes na base deste órgão e, ademais, comparação destas com as descritas cientificamente em outras espécies animais. Detectou-se a presença das artérias vertebral direita e esquerda, próximas à medula oblonga, originando a artéria basilar, que se dividiu nos ramos terminais da artéria basilar direito e esquerdo. Ventral ao trato óptico verificou-se a artéria carótida interna direita e esquerda dividindo-se na artéria cerebral média e rostral direita e esquerda; ainda, dorsal ao quiasma óptico, identificou-se o ramo medial das artérias cerebrais rostrais. Com base nos resultados obtidos, conclui-se que a vascularização da base do encéfalo da paca é suprida pelo sistema carotídeo e vertebro-basilar.(AU)

Effects of dexmedetomidine combined with commonly administered opioids on clinical variables in dogs.

OBJECTIVE To evaluate cardiopulmonary, sedative, and antinociceptive effects of dexmedetomidine combined with commonly administered opioids in dogs. ANIMALS 8 healthy Beagles. PROCEDURES Dogs were sedated by IM administration of each of 7 treatments. Treatments comprised dexmedetomidine (0.01 mg/kg; Dex) and the same dose of dexmedetomidine plus butorphanol (0.15 mg/kg; Dex-But), meperidine (5 mg/kg; Dex-Mep), methadone (0.5 mg/kg; Dex-Meth), morphine (0.5 mg/kg; Dex-Mor), nalbuphine (0.5 mg/kg; Dex-Nal), or tramadol (5 mg/kg; Dex-Tram). Cardiorespiratory and arterial blood gas variables and sedative and antinociceptive scores were measured before drug injection (time 0; baseline) and at 15-minute intervals for 120 minutes. RESULTS Heart rate was reduced at all time points after injection of Dex-But, Dex-Mep, Dex-Meth, and Dex-Mor treatments. There was a significant reduction of mean arterial blood pressure for Dex-But, Dex-Mep, and Dex-Mor treatments at all time points, compared with baseline. There was a significant decrease in respiratory rate, compared with the baseline value, for Dex, Dex-But, Dex-Meth, and Dex-Tram treatments from 15 to 120 minutes. A significant decrease in arterial blood pH was detected from baseline to 120 minutes for all treatments, with differences among Dex, Dex-Mep, and Dex-Mor. Reduction in Pao2 was greater for the Dex-Mep treatment than for the other treatments. The highest sedation scores were detected for Dex-Mep and Dex-Meth treatments. Antinociceptive effects were superior for Dex-But, Dex-Meth, Dex-Mor, and Dex-Nal treatments. CONCLUSIONS AND CLINICAL RELEVANCE Drug combinations caused similar cardiorespiratory changes, with greater sedative effects for Dex-Mep and Dex-Meth and superior antinociceptive effects for Dex-But, Dex-Meth, Dex-Mor, and Dex-Nal.