Figure 1.
Initial 100 amino acids of the alignment of partial TRPV1 genes, showing a shared indel in the reptilian clade that is absent from the common ancestor, Xenopus tropicalis. Fragments were ∼650 bp (Crocodylus porosus, Poephila guttata, Coturnix chinensis) and ∼350 bp (Pseudomoia entrecasteauxii and Amphibolurus muricatus) (a). Phylogenetic relationships of partial TRPV1 and 2 genes based on an alignment of amino acids and analysed using Bayesian Inference (BI). The numbers at nodes indicate posterior probabilities and ML bootstrap values (BI/ML) for clades where these exceed 50%. The new sequences from this work are in red. The reptilian clade is shown in yellow. The full alignment is available from the authors.
Figure 2.
Phylogenetic relationships of TRPM8 genes based on an alignment of amino acids, analysed using BI. The numbers at nodes indicate posterior probabilities and ML bootstrap values (BI/ML) for clades, where it exceeds 50%. The new sequence from this work is in red, and it was ∼500 bp. The full alignment is available from the authors.
Figure 3.
TRPV1 mRNA is expressed in dorsal surface muscle, liver, and heart tissues. Relative expression is significantly greater in heart than in muscle or liver.
Figure 4.
Before treatment, both control (blue lines) and experimental (red lines) animals performed characteristic shuttling behaviour between heating and cooling environments, resulting in periodic oscillations in body temperature (a). After administration of capsazepine, the body temperature of experimental animals ceased to oscillate periodically, while body temperature patterns of control animals remained unchanged (b). Both (a) and (b) show representative examples of data from the same pair of animals. Body temperature time series were transformed into a frequency domain, and the periodogram of the control and experimental animals before treatment shows regular body temperature cycles at 43 and 86 min cycle−1 (c). After treatment, these regular cycles disappear when TRPV1 and TRPM8 were blocked, but there is no change in control animals (d). Means from all animals±s.e. are shown in c and d.
Figure 5.
The total power density, i.e. the intensity of periodic body temperature cycles, is significantly less when TRPV1 and TRPM8 were blocked, compared to the other treatments which do not differ significantly from each other (CTL = control animals, EXP = experimental animals, DMSO = DMSO treatment, CAP = capsazepine treatment; means from all animals±s.e. are shown).