title: Effect of non-genomic actions of thyroid hormones on the anaesthetic effect of propofol.
abstract: Hyperthyroidism is a common disease of the endocrine system and it is known that additional propofol anaesthesia is required during surgery for patients with hyperthyroidism compared with those with normal thyroid function. The aim of the present study was to determine the mechanism through which thyroid hormones (THs) inhibit the effect of propofol anaesthesia. Immunofluorescence techniques were used to verify the difference between the expression quantities of γ-aminobutyric acid type A (GABAA) receptor subunits α2 and β2 in the dorsal root ganglions (DRGs) of rats with hyperthyroidism and those in normal rats. Perforated patch clamp recordings in the whole-cell mode were performed to detect the GABA-activated current in acutely isolated rat DRG neurons from rats with hyperthyroidism and normal rats. This method was also used to evaluate the change in the GABA-activated currents following the pre-perfusion of propofol with and without 3,3',5-L-triiodothyronine (T3). Compared with normal rats, rats with hyperthyroidism expressed same quantities of GABAAreceptor α2 and β2 subunits in DRGs. In addition, no difference in GABA-activated currents in the acutely isolated DRG neurons from the two types of rat was observed (P>0.05). T3inhibits or minimises the augmentation effect of propofol on the GABA-activated currents (P<0.05). The inhibitory effect of T3on propofol was minimised by increasing the propofol concentration (P<0.05). The inhibitory effect of T3on the anaesthetic effect of propofol is achieved through the inhibition of the function of GABAAreceptors through the non-genomic actions of the THs, rather than by changing the number of GABAAreceptors. This inhibitory effect can be mitigated by increasing the propofol concentration. In conclusion, rats with hyperthyroidism require a larger dose of propofol to induce anaesthesia since the non-genomic actions of THs suppress GABA receptors, which in turn inhibits the anaesthetic action of propofol.
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China ; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China.
authors.forename: Ketao
authors.initials: K
authors.lastname: Ma
authors.affiliation: Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China.
authors.forename: L I
authors.initials: LI
authors.lastname: Li
authors.affiliation: Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China ; Electrophysiological Laboratory, Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China ; Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China.
authors.forename: Junqiang
authors.initials: J
authors.lastname: Si
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China.
authors.forename: Y U
authors.initials: YU
authors.lastname: Wan
keywords: 3,3′,5-L-triiodothyronine; hyperthyroidism; non-genomic actions; propofol; γ-aminobutyric acid type A receptor