The Anesthetic Mechanism of Urethane: The Effects on Neurotransmitter-Gated Ion Channels

Abstract

Urethane modestly affects multiple neurotransmitter systems at an anesthetic concentration. Our findings suggest that these degenerate effects of urethane can produce anesthesia and that urethane has a potential to influence neuronal measurements made in in vivo preparations.

Basal forebrain activation enhances between-trial reliability of low-frequency local field potentials (LFP) and spiking activity in tree shrew primary visual cortex (V1)

“…In the current experiments, nAChR currents are unlikely to contribute much to the observed findings, because the corresponding ionic transmembrane currents are strongly suppressed by isoflurane anesthesia (Campagna et al 2003;Violet et al 1997). The situation differs from previous studies that employed urethane anesthesia (Goard and Dan 2009;Marguet and Harris 2011), which moderately enhances nAChR ionic currents (Haensel et al 2015;Hara and Harris 2002). In addition, while we have observed lower LFP event amplitude in the desynchronized state here, the opposite would occur with nicotinic receptor (nAChR) activation, which is expected to enhance LFP amplitudes by activating thalamocortical glutamatergic afferents (Disney et al 2007;Gil et al 1997;Kang and Vaucher 2009) and disinhibiting pyramidal cells through GABAergic neurons (Christophe et al 2002).…”

Gap junction blockers attenuate beta oscillations and improve forelimb function in hemiparkinsonian rats

“…In addition, others used this approach as a useful way to assess β oscillatory activity within and between the BG and cortex in hemiparkinsonian rats (Magill et al, 2006) and it was noted that neuronal activity with urethane treatment resembles activity observed in the awake, un-anesthetized state and does not impact on activity in the β frequency range in a number of different brain regions including the GPe or STN (Magill et al, 2006;Mallet et al, 2008a;Sharott et al, 2005); this makes urethane suitable for monitoring for the emergence and changes in β oscillations using LFP recordings (Magill et al, 2001). Lastly, urethane does not induce anesthesia by affecting GJ activity (Bocian et al, 2009;Hara and Harris, 2002).…”

Divergent response properties of layer-V neurons in rat primary auditory cortex

“…A1 neurons recorded from urethane anesthetized animals were more responsive to acoustic stimuli than cells under ketamine/xylazine or barbiturate (unpublished personal observations). Urethane was also reported to have relatively minor affects on the GABAergic systems (Hara and Harris, 2002;Maggi and Meli, 1986). Animals were placed on a homeothermic blanket with body temperature monitored via a rectal probe and maintained at 37°C.…”