1. Corresponding minimum alveolar concentrations of isoflurane and isoflurane/nitrous oxide have divergent effects on thalamic nociceptive signalling 
C. Vahle-Hinz, O. Detsch, C. Hackner, E. Kochs 
British Journal of Anaesthesia 
Volume 98, Issue 2, Pages (February 2007)
DOI: /bja/ael332
Copyright © 2007 British Journal of Anaesthesia Terms and Conditions

2. Fig 1
(a) Recording site in the pathway of the nociceptive system of the rat. DH, dorsal horn; POm, medial posterior complex; SI, primary somatosensory cortex; SpV, spinal trigeminal nucleus. (b) Camera lucida drawing of the frontal histological section holding the lesion made at the recording site of a nociceptive neuron. VP, ventroposterior nucleus; scale bar: 1 mm. (c) The neuron’s response to a radiant heat stimulus applied to the receptive field on the nose (middle trace) is shown as original spike record (upper trace) and peristimulus time histogram (lower trace). Segments taken for measurements of ongoing and response activities are marked.
British Journal of Anaesthesia  , DOI: ( /bja/ael332)
Copyright © 2007 British Journal of Anaesthesia Terms and Conditions

3. Fig 2
Divergent effects of ∼1.4 MAC of isoflurane (ISO) vs ∼1.4 MAC of isoflurane/nitrous oxide (N2O) on nociceptive responses of thalamic neurons. (a) During baseline (∼0.9 MAC isoflurane) both nociceptive neurons showed excitatory responses to noxious heat stimulation of their receptive fields (a, a′). Administration of isoflurane plus nitrous oxide suppressed the response in one neuron (b), whereas in the other neuron the response was maintained (b′). In contrast, administration of isoflurane at a corresponding MAC caused a complete response obliteration in both neurons (c, c′). Peristimulus time histograms of single responses, bin width 1 s. (b) Population data (n = 19) demonstrating that under ∼1.4 MAC isoflurane nociceptive responses were suppressed in all neurons; in contrast, under ∼1.4 MAC isoflurane/nitrous oxide responses were still present in 7 of 19 neurons. Note consistency of recovery data. *P < 0.05 vs baseline; #P < 0.05 vs responding neurons at ∼1.4 MAC isoflurane/nitrous oxide.
British Journal of Anaesthesia  , DOI: ( /bja/ael332)
Copyright © 2007 British Journal of Anaesthesia Terms and Conditions

4. Fig 3
Divergent effects of ∼1.1 MAC of isoflurane (ISO) vs ∼1.1 MAC of isoflurane/nitrous oxide (N2O) on nociceptive responses of thalamic neurons. (a) Note the increased response under ∼1.1 MAC isoflurane/nitrous oxide (b′) as compared with isoflurane at ∼ 0.9 MAC (a′) suggesting a facilitatory effect of nitrous oxide on nociceptive signalling of this neuron. Data in a′–d′ from the same neuron as in Figure 2aa–d. Conventions as in Figure 2a. (b) Population data (n = 14); *P < 0.05 vs baseline; #P < 0.05 vs responding neurons at ∼1.1 MAC isoflurane/nitrous oxide.
British Journal of Anaesthesia  , DOI: ( /bja/ael332)
Copyright © 2007 British Journal of Anaesthesia Terms and Conditions