ABSTRACT
This study evaluated the effects of high and low dosages of medetomidine-ketamine in red-eared slider turtles (Trachemys scripta elegans) and the reversibility of the anesthesia with atipamezole. Thirty healthy adult turtles were assigned randomly to one of two dosage groups. The lower dosage group received 0.1 mg medetomidine/kg body weight intramuscularly (i.m.) combined with 5 mg ketamine/kg i.m. The higher dosage group received 0.2 mg medetomidine/kg i.m. combined with 10 mg ketamine/kg i.m. Physiologic parameters evaluated included heart rate, palpebral reflex, limb and neck relaxation, and cloacal temperature. Responses to minor procedures such as i.m. injection (0.1 ml 0.9% NaCl) and endotracheal intubation also were evaluated. In addition, the higher dosage group was evaluated for responsiveness to a skin incision and placement of a skin suture. Both dosage trials resulted in a level of anesthesia deep enough for performing a physical examination, minor procedures, and endotracheal intubation. The higher dosage produced a level of anesthesia sufficient for performing a skin incision and suture placement. Heart rate and cloacal temperatures remained stable throughout the entire procedure for both groups. Atipamezole was administered i.m. at five times the dose of medetomidine (0.5 mg/kg i.m. or 1 mg/kg i.m.) 60 min after the medetomidine-ketamine was administered. All of the turtles were swimming 60 min after atipamezole administration.
Subject(s)
Analgesics, Non-Narcotic/administration & dosage , Anesthesia/veterinary , Anesthetics, Dissociative/administration & dosage , Ketamine/administration & dosage , Medetomidine/administration & dosage , Turtles/physiology , Adrenergic alpha-Agonists/pharmacology , Animals , Dose-Response Relationship, Drug , Heart Rate/drug effects , Imidazoles/pharmacology , Injections, Intramuscular/veterinary , Intubation, Intratracheal/veterinary , Muscle, Skeletal/drug effects , Random AllocationABSTRACT
The identification and molecular characterization of Brn-3.2 has revealed a family of Brn-3-related mammalian POU proteins that share homology with the C. elegans developmental regulator Unc-86 and extended similarity with the Drosophila neurodevelopmental gene I-POU, which defines a novel POU-IV box. Brn-3.2 exhibits DNA binding properties similar to those of Brn-3.0, but its expression is uniquely regulated by retinoic acid in teratocarcinoma and neuroblastoma cells. In the developing PNS and retina, the expression pattern of Brn-3.2 is similar to that of Brn-3.0. In the caudal CNS (spinal cord, hindbrain, and midbrain) Brn-3.2 and Brn-3.0 are initially coexpressed, but diverge later in development. Rostral to the midbrain, Brn-3.2 and Brn-3.0 exhibit nonoverlapping patterns of expression, suggesting divergence of gene function in more recently evolved structures. Our analysis suggests that in the CNS Brn-3.2 is selectively expressed in postmitotic neurons, implying a role in specifying terminally differentiated neuronal phenotypes.
Subject(s)
Brain/metabolism , DNA-Binding Proteins/biosynthesis , Gene Expression Regulation/physiology , Homeodomain Proteins , Neurons/metabolism , Spinal Cord/metabolism , Transcription Factors/biosynthesis , Tretinoin/pharmacology , Amino Acid Sequence , Animals , Base Sequence , Cell Differentiation , Cell Line , DNA, Complementary/metabolism , Drosophila/physiology , Embryo, Mammalian , Embryo, Nonmammalian , Gene Expression/drug effects , Gene Expression Regulation/drug effects , Gene Library , Genes, Homeobox , In Situ Hybridization , Mesencephalon/metabolism , Mice , Mitosis , Molecular Sequence Data , Neuroblastoma , Neurons/cytology , Neurons/drug effects , Organ Specificity , Rhombencephalon/metabolism , Sequence Homology, Amino Acid , Teratoma , Transcription Factor Brn-3 , Transcription Factor Brn-3A , Transcription Factor Brn-3B , Transfection , Tumor Cells, CulturedABSTRACT
Characterization of Brn-3.0 and identification of a highly related member (Brn-3.1) of the class IV POU-domain family suggest potential roles of Brn-3.0 in the development of retinal ganglion cells and sensory neurons, as well as potential roles in the pituitary gland and the immune system. Brn-3.0 is expressed in the pituitary gland and in a corticotroph cell line. A functional DNA response element has been identified in the proopiomelanocortin promoter. In contrast to previously described mammalian POU-domain proteins, Brn-3.0 binds relatively ineffectively to known octamer DNA motifs, but instead binds with high affinity to a distinct set of DNA elements, functioning as a transcriptional activator. Brn-3.0, Brn-3.1, and the Drosophila tI-POU share an N-terminal region of homology, referred to as the "POU-IV box," which is similar to a conserved functional domain in the c-myc gene family.
