RESUMO
The objective of the study was to examine the changes in central nervous system (CNS) activity and physical behaviour during induction and awakening from CO2 anaesthesia. Two studies, each using pigs immersed into 90% CO2 gas for a period of 60 s were performed. In study 1, we monitored middle latency auditory evoked potentials (changes in latencies, amplitudes and a depth of anaesthesia index), electroencephalographic parameters (delta, theta, alpha and beta electroencephalographic power and 95% spectral edge frequency) and heart rate; and in study 2, we monitored body movements and arterial and venous partial pressure of CO2 and O2. No behavioural signs of distress were observed during the early part of the induction. The swine exhibited muscular activity from 13-30 s after induction-start as well as during awakening from anaesthesia, possibly because of a transitory weaker suppression of the brain stem than of the cortex. The CNS and blood gas parameters started to change from the very start of induction. The CNS suppression lasted only approximately one minute after the end of the induction period. The two studies indicated a good temporal relationship between changes in amplitude, depth of anaesthesia index, spectral edge frequency, and arterial PCO2 during the induction period.
Assuntos
Anestesia por Inalação/veterinária , Dióxido de Carbono/administração & dosagem , Sistema Nervoso Central/efeitos dos fármacos , Administração por Inalação , Anestesia por Inalação/efeitos adversos , Animais , Comportamento Animal/efeitos dos fármacos , Dióxido de Carbono/sangue , Sistema Nervoso Central/fisiopatologia , Eletroencefalografia/efeitos dos fármacos , Eletroencefalografia/veterinária , Potenciais Evocados Auditivos/efeitos dos fármacos , Potenciais Evocados Auditivos/fisiologia , Feminino , Exposição por Inalação , Masculino , Movimento/efeitos dos fármacos , Movimento/fisiologia , SuínosRESUMO
The conformational properties in solution of the glycans on the alpha subunit of recombinant human chorionic gonadotropin are described, using high-resolution multinuclear NMR studies on uniformly 13C, 15N-enriched recombinant glycoprotein expressed in CHO cells. The glycan important for full biological activity of hCG, namely, that at Asn 52, appears to extend into solution both in the isolated alpha subunit and in complex with the beta subunit. The disposition of this glycan with respect to the protein backbone suggests that glycosylation maintains full biological activity of hCG either by interacting with a lectin-like region of the hCG receptor or by reducing the affinity of the hormone for the hCG receptor and preventing its down-regulation.
