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1.
FASEB J ; 29(5): 1794-804, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25563298

RESUMO

Rem, Rad, Kir/Gem (RGK) proteins, including Rem2, mediate profound inhibition of high-voltage activated Ca(2+) channels containing intracellular regulatory ß subunits. All RGK proteins bind to voltage-gated Ca(2+) channel ß subunit (Cavß) subunits in vitro, but the necessity of the interaction for current inhibition remains controversial. This study applies NMR and calorimetric techniques to map the binding site for Rem2 on human Cavß4a and measure its binding affinity. Our experiments revealed 2 binding surfaces on the ß4 guanylate kinase domain contributing to a 156 ± 18 µM Kd interaction: a hydrophobic pocket lined by 4 critical residues (L173, N261, H262, and V303), mutation of any of which completely disrupted binding, and a nearby surface containing 3 residues (D206, L209, and D258) that when individually mutated decreased affinity. Voltage-gated Ca(2+) channel α1A subunit (Cav2.1) Ca(2+) currents were completely inhibited by Rem2 when co-expressed with wild-type Cavß4a, but were unaffected by Rem2 when coexpressed with a Cavß4a site 1 (L173A/V303A) or site 2 (D258A) mutant. These results provide direct evidence for a low-affinity Rem2/Cavß4 interaction and show definitively that the interaction is required for Cav2.1 inhibition.


Assuntos
Canais de Cálcio Tipo N/química , Canais de Cálcio Tipo N/metabolismo , Calorimetria/métodos , Canais Iônicos/fisiologia , Espectroscopia de Ressonância Magnética/métodos , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Canais de Cálcio Tipo N/genética , Eletrofisiologia , Células HEK293 , Humanos , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas
2.
J Biol Chem ; 286(11): 9677-87, 2011 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-21220418

RESUMO

The ß subunits of voltage-gated Ca(2+) channels are best known for their roles in regulating surface expression and gating of voltage-gated Ca(2+) channel α(1) subunits. Recent evidence, however, indicates that these proteins have a variety of Ca(2+) channel-independent functions. For example, on the molecular level, they regulate gene expression, and on the whole animal level, they regulate early cell movements in zebrafish development. In the present study, an alternatively spliced, truncated ß4 subunit (ß4c) is identified in the human brain and shown to be highly expressed in nuclei of vestibular neurons. Pull-down assays, nuclear magnetic resonance, and isothermal titration calorimetry demonstrate that the protein interacts with the chromo shadow domain (CSD) of heterochromatin protein 1γ. Site-directed mutagenesis reveals that the primary CSD interaction occurs through a ß4c C-terminal PXVXL consensus motif, adding the ß4c subunit to a growing PXVXL protein family with epigenetic responsibilities. These proteins have multiple nuclear functions, including transcription regulation (TIF1α) and nucleosome assembly (CAF1). An NMR-based two-site docking model of ß4c in complex with dimerized CSD is presented. Possible roles for the interaction are discussed.


Assuntos
Canais de Cálcio/metabolismo , Núcleo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Processamento Alternativo/fisiologia , Animais , Canais de Cálcio/genética , Núcleo Celular/genética , Homólogo 5 da Proteína Cromobox , Proteínas Cromossômicas não Histona/genética , Exorribonucleases , Humanos , Camundongos , Mutagênese Sítio-Dirigida , Proteínas do Tecido Nervoso/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Ligação Proteica , Proteínas/genética , Proteínas/metabolismo , Proteínas Repressoras , Ribonucleases , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética
3.
Vet Anaesth Analg ; 36(6): 567-73, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19845929

RESUMO

OBSERVATIONS: A 1-month-old Nubian goat presented for sialocyst resection. Physical examination and bloodwork were unremarkable. While pre-oxygenating, the goat was sedated with midazolam and morphine (0.1 mg kg(-1) each) intravenously (IV). General anesthesia was induced 5 minutes later with 1.7 mg kg(-1) propofol. Sevoflurane was administered in oxygen without assisted ventilation via a cuffed orotracheal tube. Throughout the first 85 minutes of anesthesia, the goat was well-oxygenated (SpO(2), > or =97%), ventilating adequately (Pe'CO(2), 36-48 mmHg), and had normal mean arterial blood pressure (MAP, 60-85 mmHg). Blood-gas values at 45 minutes were consistent with adequate ventilation on oxygen. At 75 minutes, the goat moved in response to surgical stimulation, requiring additional propofol (0.4 mg kg(-1)). After 10 minutes, MAP dropped precipitously to 40 mmHg and frequent multiform premature ventricular contractions (PVCs) were observed. Crystalloids, hetastarch, and dopamine (5 mug kg(-1) minute(-1)) were administered to correct the hypotension. Arterial blood-gas analysis revealed that the goat had become hypoxemic (PaO(2), 50 mmHg). Intermittent positive pressure ventilation (IPPV) was initiated. Subsequent blood-gas analysis did not show significant improvement in PaO(2) (53 and 56 mmHg, respectively). Occasional PVCs were observed thereafter. Surgery ended, and sevoflurane and IPPV were discontinued. The goat was extubated within 7 minutes and received 100% oxygen by mask. Diffuse crackles were ausculted over both hemithoraces. Suspecting pulmonary edema, furosemide (1 mg kg(-1)) was administered IV. Radiographs taken immediately post-operatively revealed a severe, caudodorsal airspace (alveolar) pattern, confirming the diagnosis. Respiration improved considerably within an hour with nasal oxygen and two additional doses of furosemide. CONCLUSIONS: The goat developed acute, drug-induced, noncardiogenic pulmonary edema in response to the second dose of propofol.


Assuntos
Anestésicos Intravenosos/efeitos adversos , Doenças das Cabras/induzido quimicamente , Propofol/efeitos adversos , Edema Pulmonar/veterinária , Anestesia Geral/efeitos adversos , Anestesia Geral/veterinária , Animais , Diuréticos/uso terapêutico , Feminino , Furosemida/uso terapêutico , Cabras , Oxigênio/uso terapêutico , Edema Pulmonar/induzido quimicamente , Edema Pulmonar/tratamento farmacológico
4.
Mol Pharmacol ; 74(3): 904-12, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18583457

RESUMO

Gabapentin is well established as an effective treatment for neuropathic pain; however, little is known about its mechanism of action. It binds with high affinity to Ca2+ channel alpha2delta subunits that are expressed in dorsal root ganglia. Mutation of a single alpha2delta amino acid, R217A, eliminates both gabapentin binding and analgesic efficacy. Gabapentin does not seem to have direct Ca2+ channel blocking properties but does affect overall levels of Ca2+channel surface expression in some circumstances. In this report, we examined gabapentin effects on trafficking and voltage-dependent gating properties of recombinant Ca(v)2.1 Ca2+ channel complexes transiently expressed in Xenopus laevis oocytes. We also determined electrophysiologically whether gabapentin causes displacement of beta subunits from Ca(v)2.1 complexes. Our principal findings are as follows: 1) gabapentin inhibits trafficking of recombinant Ca(v)2.1 Ca2+ channels in X. laevis oocytes; 2) gabapentin inhibition occurs in the presence of the Ca2+ channel beta4a subunit but not in the presence of beta4b; 3) gabapentin does not affect Ca(v)2.1 voltage-dependent gating parameters; 4) inhibition of Ca(v)2.1 trafficking is highly dependent on beta-subunit concentration; and 5) gabapentin inhibition of Ca(v)2.1 trafficking can be reversed by the alpha2delta R217A mutation. Overall, our results suggest that gabapentin reduces the number of beta4a-bound Ca(v)2.1 complexes that are successfully trafficked to the plasma membrane. This mechanism may help to explain why gabapentin is both effective and selective in the treatment of neuropathic pain states that involve up-regulation of alpha2delta subunits.


Assuntos
Processamento Alternativo/efeitos dos fármacos , Aminas/farmacologia , Canais de Cálcio Tipo N/metabolismo , Canais de Cálcio/genética , Ácidos Cicloexanocarboxílicos/farmacologia , Subunidades Proteicas/metabolismo , Ácido gama-Aminobutírico/farmacologia , Alanina/genética , Animais , Arginina/genética , Gabapentina , Humanos , Ativação do Canal Iônico/efeitos dos fármacos , Modelos Biológicos , Mutação/genética , Isoformas de Proteínas/metabolismo , Transporte Proteico/efeitos dos fármacos , Coelhos , Xenopus
5.
Physiol Genomics ; 35(2): 133-44, 2008 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-18682574

RESUMO

The Ca(2+) channel beta-subunits, encoded by CACNB genes 1-4, are membrane-associated guanylate kinase (MAGUK) proteins. As auxiliary subunits of voltage-gated Ca(2+) channels, the beta-subunits facilitate membrane trafficking of the pore-forming alpha1 subunits and regulate voltage-dependent channel gating. In this report, we investigate whether two zebrafish beta4 genes, beta4.1 and beta4.2, have diverged in structure and function over time. Comparative expression analyses indicated that beta4.1 and beta4.2 were expressed in separable domains within the developing brain and other tissues. Alternative splicing in both genes was subject to differential temporal and spatial regulation, with some organs expressing different subsets of beta4.1 and beta4.2 transcript variants. We used several genomic tools to identify and compare predicted cDNAs for eight teleost and five tetrapod beta4 genes. Teleost species had either one or two beta4 paralogs, whereas each tetrapod species contained only one. Teleost beta4.1 and beta4.2 genes had regions of sequence divergence, but compared with tetrapod beta4s, they exhibited similar exon/intron structure, strong conservation of residues involved in alpha1 subunit binding, and similar 5' alternative splicing. Phylogenetic results are consistent with the duplicate teleost beta4 genes resulting from the teleost whole genome duplication. Following duplication, the beta4.1 genes have evolved faster than beta4.2 genes. We identified disproportionately large second and third introns in several beta4 genes, which we propose may provide regulatory elements contributing to their differential tissue expression. In sum, both mRNA expression data and phylogenetic analysis support the evolutionary divergence of beta4.1 and beta4.2 subunit function.


Assuntos
Canais de Cálcio/classificação , Canais de Cálcio/genética , Genoma , Processamento Alternativo , Sequência de Aminoácidos , Animais , Canais de Cálcio/metabolismo , Evolução Molecular , Expressão Gênica , Genômica , Humanos , Hibridização In Situ , Íntrons , Dados de Sequência Molecular , Filogenia , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Vertebrados , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
6.
J Neurosci ; 26(10): 2635-44, 2006 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-16525042

RESUMO

Ca2+ channel beta subunits regulate cell-surface expression and gating of voltage-dependent Ca2+ channel alpha1 subunits. Based on primary sequence comparisons, beta subunits are predicted to be modular structures composed of five domains (A-E) that are related to the large family of membrane-associated guanylate kinase proteins. The crystal structure of the beta subunit core B-D domains has been reported recently; however, little is known about the structures of the A and E domains. The N-terminal A domain differs among the four subtypes of Ca2+ channel beta subunits (beta1-beta4) primarily as the result of two duplications of an ancestral gene containing multiple alternatively spliced exons. At least nine A domain sequences can be generated by alternative splicing. In this report, we focus on one A domain sequence, the highly conserved beta4a A domain. We solved its three-dimensional structure and show that it is expressed in punctate structures throughout the molecular layer of the cerebellar cortex. We also demonstrate that it does not participate directly in Cav2.1 Ca2+ channel gating but serves as a binding site in protein-protein interactions with synaptotagmin I and the LC2 domain of microtubule-associated protein 1A. With respect to beta4 subunits, the interactions are specific for the beta4a splice variant, because they do not occur with the beta4b A domain. These results have strong bearing on our current understanding of the structure of alternatively spliced Ca2+ channel beta subunits and the cell-specific roles they play in the CNS.


Assuntos
Processamento Alternativo , Canais de Cálcio/química , Canais de Cálcio/metabolismo , Cerebelo/metabolismo , Expressão Gênica/fisiologia , Animais , Western Blotting/métodos , Canais de Cálcio/genética , Cerebelo/citologia , Relação Dose-Resposta à Radiação , Estimulação Elétrica/métodos , Biblioteca Gênica , Humanos , Imuno-Histoquímica/métodos , Ativação do Canal Iônico/fisiologia , Espectroscopia de Ressonância Magnética/métodos , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Potenciais da Membrana/efeitos da radiação , Camundongos , Camundongos Endogâmicos C57BL , Microinjeções/métodos , Modelos Moleculares , Dados de Sequência Molecular , Oócitos , Técnicas de Patch-Clamp/métodos , Ligação Proteica , Conformação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Sinaptotagmina I/metabolismo , Técnicas do Sistema de Duplo-Híbrido , Xenopus
7.
Protein Sci ; 15(2): 378-83, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16385006

RESUMO

Ca2+ channel beta subunits regulate trafficking and gating (opening and closing) of voltage-dependent Ca2+ channel alpha1 subunits. Based on primary sequence comparisons, they are thought to be modular structures composed of five domains (A-E) that are related to the large family of membrane associated guanylate-kinase (MAGUK) proteins. The crystal structures of the beta subunit core, B-D, domains have recently been reported; however, very little is known about the structures of the A and E domains. The N-terminal A domain is a hypervariable region that differs among the four subtypes of Ca2+ channel beta subunits (beta1-beta4). Furthermore, this domain undergoes alternative splicing to create multiple N-terminal structures within a given gene class that have distinct effects on gating. We have solved the solution structure of the A domain of the human beta4a subunit, a splice variant that we have shown previously to have alpha1 subunit subtype-specific effects on Ca2+ channel trafficking and gating.


Assuntos
Canais de Cálcio/química , Canais de Cálcio/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Cálcio/metabolismo , Canais de Cálcio/genética , Cristalização , Cristalografia por Raios X , Dimerização , Humanos , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Dados de Sequência Molecular , Conformação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Soluções
8.
J Neurosci ; 22(5): 1573-82, 2002 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11880487

RESUMO

Ca2+ channel beta subunits are important molecular determinants of the kinetics and voltage dependence of Ca2+ channel gating. Through direct interactions with channel-forming alpha1 subunits, beta subunits enhance expression levels, accelerate activation, and have variable effects on inactivation. Four distinct beta subunit genes each encode five homologous sequence domains (D1-5), three of which (D1, D3, and D5) undergo alternative splicing. We have isolated from human spinal cord a novel alternatively spliced beta4 subunit containing a short form of domain D1 (beta4a) that is highly homologous to N termini of Xenopus and rat beta3 subunits. The purpose of this study was to compare the gating properties of various alpha1 subunit complexes containing beta4a with those of complexes containing a beta4 subunit with a longer form of domain D1, beta4b. Expression in Xenopus oocytes revealed that, relative to alpha1A and alpha1B complexes containing beta4b, the voltage dependence of activation and inactivation of complexes containing beta4a were shifted to more depolarized potentials. Moreover, alpha1A and alpha1B complexes containing beta4a inactivated at a faster rate. Interestingly, beta4 subunit alternative splicing did not influence the gating properties of alpha1C and alpha1E subunits. Experiments with beta4 deletion mutants revealed that both the N and C termini of the beta4 subunit play critical roles in setting voltage-dependent gating parameters and that their effects are alpha1 subunit specific. Our data are best explained by a model in which distinct modes of activation and inactivation result from beta-subunit splice variant-specific interactions with an alpha1 subunit gating structure.


Assuntos
Processamento Alternativo , Canais de Cálcio/metabolismo , Ativação do Canal Iônico/fisiologia , Subunidades Proteicas , Adolescente , Adulto , Idoso , Animais , Canais de Cálcio/genética , Clonagem Molecular , Feminino , Expressão Gênica , Humanos , Masculino , Potenciais da Membrana/fisiologia , Pessoa de Meia-Idade , Modelos Biológicos , Dados de Sequência Molecular , Oócitos/metabolismo , Técnicas de Patch-Clamp , RNA Complementar/genética , RNA Complementar/metabolismo , Deleção de Sequência , Homologia de Sequência de Aminoácidos , Medula Espinal/metabolismo , Relação Estrutura-Atividade , População Branca , Xenopus
9.
J Neurosci ; 22(21): 9331-9, 2002 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-12417658

RESUMO

Ca2+ channel beta subunits modify alpha1 subunit gating properties through direct interactions with intracellular linker domains. In a previous report (Helton and Horne, 2002), we showed that alternative splicing of the beta4 subunit had alpha1 subunit subtype-specific effects on Ca2+ channel activation and fast inactivation. We extend these findings in the present report to include effects on slow inactivation and block by the peptide toxin omega-conotoxin (CTx)-MVIIC. N-terminal deletion and site-directed mutagenesis experiments revealed that the effects of alternative splicing on toxin block and all aspects of gating could be attributed to a proline-rich motif found within N-terminal beta4b amino acids 10-20. Interestingly, this motif is conserved within the third postsynaptic density-95 (PSD-95)/Discs large/zona occludens-1 domain of the distantly related membrane-associated guanylate kinase homolog, PSD-95. Sequence identity of approximately 30% made possible the building of beta4a and beta4b three-dimensional structural models using PSD-95 as the target sequence. The models (1) reveal that alternative splicing of the beta4 N terminus results in dramatic differences in surface charge distribution and (2) localize the proline-rich motif of beta4b to an extended arm structure that flanks what would be the equivalent of a highly modified PSD-95 carboxylate binding loop. Northern blot analysis revealed a markedly different pattern of distribution for beta4a versus beta4b in the human CNS. Whereas beta4a is distributed throughout evolutionarily older regions of the CNS, beta4b is concentrated heavily in the forebrain. These results raise interesting questions about the functional role that alternative splicing of the beta4 subunit has played in the evolution of complex neural networks.


Assuntos
Processamento Alternativo/fisiologia , Canais de Cálcio Tipo N/genética , Canais de Cálcio Tipo N/metabolismo , Ativação do Canal Iônico/fisiologia , ômega-Conotoxinas/farmacologia , Motivos de Aminoácidos/fisiologia , Animais , Encéfalo/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo N/efeitos dos fármacos , Humanos , Ativação do Canal Iônico/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Proteínas do Tecido Nervoso/genética , Oócitos/metabolismo , Especificidade de Órgãos , Técnicas de Patch-Clamp , Estrutura Terciária de Proteína/fisiologia , Subunidades Proteicas/efeitos dos fármacos , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , RNA Mensageiro/metabolismo , Deleção de Sequência , Homologia de Sequência de Aminoácidos , Medula Espinal/metabolismo , Relação Estrutura-Atividade , Xenopus laevis
10.
J Am Vet Med Assoc ; 221(7): 1019-25, 2002 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-12369681

RESUMO

OBJECTIVE: To determine safety and efficacy of an anesthetic protocol incorporating medetomidine, ketamine, and sevoflurane for anesthesia of injured loggerhead sea turtles. DESIGN: Retrospective study. ANIMALS: 13 loggerhead sea turtles. PROCEDURE: Anesthesia was induced with medetomidine (50 microg/kg [22.7 microg/lb], IV) and ketamine (5 mg/kg (2.3 mg/lb], IV) and maintained with sevoflurane (0.5 to 2.5%) in oxygen. Sevoflurane was delivered with a pressure-limited intermittent-flow ventilator. Heart rate and rhythm, end-tidal partial pressure of CO2, and cloacal temperature were monitored continuously; venous blood gas analyses were performed intermittently. Administration of sevoflurane was discontinued 30 to 60 minutes prior to the end of the surgical procedure. Atipamezole (0.25 mg/kg [0.11 mg/lb], IV) was administered at the end of surgery. RESULTS: Median induction time was 11 minutes (range, 2 to 40 minutes; n = 11). Median delivered sevoflurane concentrations 15, 30, 60, and 120 minutes after intubation were 2.5 (n = 12), 1.5 (12), 1.25 (12), and 0.5% (8), respectively. Heart rate decreased during surgery to a median value of 15 beats/min (n = 11). End-tidal partial pressure of CO2 ranged from 2 to 16 mm Hg (n = 8); median blood gas values were within reference limits. Median time from atipamezole administration to extubation was 14 minutes (range, 2 to 84 minutes; n = 7). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a combination of medetomidine and ketamine for induction and sevoflurane for maintenance provides safe, effective, controllable anesthesia in injured loggerhead sea turtles.


Assuntos
Anestésicos Combinados , Anestésicos Dissociativos , Anestésicos Inalatórios , Hipnóticos e Sedativos , Tartarugas/fisiologia , Animais , Gasometria/veterinária , Relação Dose-Resposta a Droga , Feminino , Frequência Cardíaca/efeitos dos fármacos , Ketamina , Masculino , Medetomidina , Éteres Metílicos , Pressão Parcial , Estudos Retrospectivos , Segurança , Sevoflurano , Fatores de Tempo , Resultado do Tratamento , Tartarugas/lesões
11.
J Zoo Wildl Med ; 34(1): 47-52, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12723799

RESUMO

The cardiorespiratory effects, effectiveness, and reversibility of two injectable anesthetic combinations were compared in captive patas monkeys (Erythrocebus patas). Seven patas monkeys were hand-injected with medetomidine (40 microg/kg, i.m.), butorphanol (0.4 mg/kg. i.m.), and ketamine (3.0 mg/kg. i.m.), and seven were injected with the same dosages of medetomidine and butorphanol plus midazolam (0.3 mg/kg, i.m.). Heart rates decreased in monkeys in both treatment groups and were lower than those previously recorded in patas monkeys anesthetized with either ketamine or ketamine and isoflurane. Mean arterial pressures were highest in ketamine-treated monkeys but remained within normal limits for both groups. End tidal CO2 values increased gradually over time in both groups and were above physiologic norms after 20 min. Respiratory rates were similar between groups and remained constant throughout the procedures. Despite adequate ventilation parameters, initial low percent oxygen-hemoglobin saturation (SpO2) values were suggestive of severe hypoxemia. It was not clear whether these were accurate readings or an artifact of medetomidine-induced peripheral vasoconstriction. Oxygen supplementation restored SpO2 values to normal (>94%) in both groups. Both combinations effectively produced a state of light anesthesia, although spontaneous recoveries occurred after 30 min in three ketamine-treated monkeys. All monkeys were given i.m. atipamezole (0.2 mg/kg) and naloxone (0.02 mg/kg), whereas midazolam-treated monkeys also received flumazenil (0.02 mg/kg, i.v.), which resulted in faster (median recovery time = 5 min) and more complete recoveries in this group. Both combinations are safe to use when supplemented with oxygen, although the midazolam combination provided a longer anesthetic period and was more fully reversible.


Assuntos
Anestésicos Combinados , Pressão Sanguínea/efeitos dos fármacos , Erythrocebus patas/fisiologia , Frequência Cardíaca/efeitos dos fármacos , Respiração/efeitos dos fármacos , Analgésicos Opioides , Anestésicos Dissociativos , Anestésicos Intravenosos , Animais , Gasometria/veterinária , Temperatura Corporal/efeitos dos fármacos , Butorfanol , Feminino , Hipnóticos e Sedativos , Ketamina , Masculino , Medetomidina , Midazolam , Oximetria/veterinária , Distribuição Aleatória , Fatores de Tempo
12.
J Zoo Wildl Med ; 34(2): 163-70, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12885134

RESUMO

The relative efficacies and cardiorespiratory effects of three injectable anesthetic combinations containing medetomidine were evaluated in ring-tailed lemurs (Lemur catta). In addition, the direct effects of medetomidine on heart rate and blood pressure were evaluated in lemurs anesthetized with isoflurane. For injectable anesthesia, captive adult ring-tailed lemurs were anesthetized with medetomidine and ketamine (0.04-0.06 mg/kg, i.m. and 3 mg/kg, i.m., respectively), medetomidine, butorphanol, and ketamine (0.04 mg/kg, i.m., 0.4 mg/kg, i.m., and 3 mg/kg, i.m., respectively), or medetomidine, butorphanol, and midazolam (0.04 mg/kg, i.m., 0.4 mg/kg, i.m., and 0.3 mg/kg, i.m., respectively). For inhalation anesthesia, lemurs were mask-induced and maintained with isoflurane for 30 min before receiving medetomidine (0.04 mg/kg, i.m.). Sedation produced by medetomidine-ketamine was unpredictable and of short duration. Both medetomidine-butorphanol-ketamine (MBK) and medetomidine-butorphanol-midazolam (MBMz) provided adequate anesthesia for routine physical exams; however, the effects of MBMz lasted longer than those of MBK. Heart rates and respiratory rates were within clinically normal ranges for all groups, and lemurs remained normotensive throughout the study. Common side effects such as hypertension and bradycardia associated with the use of alpha2-adrenergic receptor agonist combinations in other species were not observed. Likewise, medetomidine administration had no effect on HR in lemurs receiving isoflurane. Lemurs in all groups were well ventilated and remained well oxygenated throughout the procedures, though arterial partial pressure of O2 was lowest in the MBMz group. All three injectable medetomidine combinations were effective in ring-tailed lemurs but only MBK and MBMz provided adequate depth and duration of anesthesia for use as sole regimes. For many clinical procedures in lemurs, MBMz offers advantages over MBK because of its longer duration of action and its rapid and more complete reversibility with specific antagonists.


Assuntos
Anestésicos Combinados/administração & dosagem , Pressão Sanguínea/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Hipnóticos e Sedativos/administração & dosagem , Lemur/fisiologia , Medetomidina/administração & dosagem , Respiração/efeitos dos fármacos , Anestésicos Dissociativos , Anestésicos Intravenosos , Animais , Gasometria/veterinária , Butorfanol , Relação Dose-Resposta a Droga , Feminino , Ketamina , Masculino , Midazolam , Fatores de Tempo , Resultado do Tratamento
13.
J Zoo Wildl Med ; 33(2): 101-7, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12398296

RESUMO

Safe, effective, and reversible immobilization protocols are essential for the management of free-ranging red wolves (Canis rufus). Combinations using an alpha2-adrenoceptor agonist and ketamine have been shown to be effective for immobilization but are not reversible and can produce severe hypertension and prolonged or rough recoveries. To minimize hypertension and provide reversibility, 24 red wolves were immobilized using three medetomidine-butorphanol (MB) combinations without the use of ketamine in the initial injection. All wolves were administered medetomidine (0.04 mg/kg i.m.) and butorphanol (0.4 mg/kg i.m.). Seven wolves received no other immobilization agents (MB wolves), nine received diazepam (0.2 mg/kg i.v.) at the time they were instrumented (MBD wolves), and eight received ketamine (1 mg/kg i.v.) 30 min after instrumentation (MBK30 wolves). Physiologic parameters were monitored during immobilization. The heart rate was similar among the three groups for the first 30 min, and marked bradycardia was noted in one wolf from each group. Hypertension was observed initially in all three groups but was resolved within 10-30 min. The MBK30 wolves had significant elevations in heart rate and transient hypertension after intravenous ketamine administration. Most wolves had mild to moderate metabolic acidemia. Immobilizing drugs were antagonized in all wolves with atipamezole (0.2 mg/kg i.m.) and naloxone (0.02 mg/kg i.m.). The medetomidine-butorphanol-diazepam wolves were also given flumazenil (0.04 mg/kg i.v.). All wolves were standing within 12 min and were fully recovered within 17 min. Medetomamine-butorphanol and MBD combinations provided effective and reversible immobilization of red wolves without the sustained hypertension associated with the use of alpha2-adrenoceptor agonist-ketamine combinations. Delaying the administration of ketamine reduced its hypertensive effects.


Assuntos
Anestésicos Dissociativos , Hipnóticos e Sedativos , Imobilização , Entorpecentes , Lobos/fisiologia , Antagonistas Adrenérgicos alfa/farmacologia , Anestésicos Dissociativos/efeitos adversos , Anestésicos Dissociativos/antagonistas & inibidores , Animais , Animais de Zoológico/fisiologia , Pressão Sanguínea/efeitos dos fármacos , Temperatura Corporal/efeitos dos fármacos , Butorfanol/efeitos adversos , Butorfanol/antagonistas & inibidores , Diazepam/efeitos adversos , Diazepam/antagonistas & inibidores , Combinação de Medicamentos , Feminino , Flumazenil/farmacologia , Moduladores GABAérgicos/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Hipertensão/induzido quimicamente , Hipnóticos e Sedativos/efeitos adversos , Hipnóticos e Sedativos/antagonistas & inibidores , Imidazóis/farmacologia , Ketamina/efeitos adversos , Ketamina/antagonistas & inibidores , Masculino , Medetomidina/efeitos adversos , Medetomidina/antagonistas & inibidores , Relaxamento Muscular/efeitos dos fármacos , Naloxona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Entorpecentes/efeitos adversos , Respiração/efeitos dos fármacos
14.
Biomol NMR Assign ; 8(1): 217-20, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23712306

RESUMO

The ß subunit of the voltage-gated Ca(2+) channel (α1, α2δ, and ß subunits) is a member of the MAGUK family of proteins and plays an essential role in regulating Ca(2+) channel trafficking and gating. It also serves as a central interaction partner for various Ca(2+) channel regulatory proteins. We report here the nearly complete (1)H, (13)C, and (15)N backbone resonance assignments of the 37 kDa core SH3-GK domains of the ß4 subunit. This is the first report of solution assignments for ß subunits, and as such will lay the foundation for future investigations of interaction site mapping, functional dynamics, and protein complex structure determination.


Assuntos
Canais de Cálcio/química , Ressonância Magnética Nuclear Biomolecular , Subunidades Proteicas/química , Sequência de Aminoácidos , Isótopos de Carbono , Humanos , Hidrogênio , Dados de Sequência Molecular , Peso Molecular , Isótopos de Nitrogênio , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína
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