Dataset Information

Functional analysis of thermo-sensitive TRPV1 in an aquatic vertebrate, masu salmon (Oncorhynchus masou ishikawae)

ABSTRACT: Transient receptor potential vanilloid 1 (TRPV1) is mainly expressed in nociceptive primary sensory neurons and acts as a sensor for heat and capsaicin. The functional properties of TRPV1 have been reported to vary among species and, in some cases, the species difference in its thermal sensitivity is likely to be associated with thermal habitat conditions. To clarify the functional properties and physiological roles of TRPV1 in aquatic vertebrates, we examined the temperature and chemical sensitivities of TRPV1 in masu salmon (Oncorhynchus masou ishikawae, Om) belonging to a family of salmonids that generally prefer cool environments. First, behavioral experiments were conducted using a video tracking system. Application of capsaicin, a TRPV1 agonist, induced locomotor activities in juvenile Om. Increasing the ambient temperature also elicited locomotor activity potentiated by capsaicin. RT-PCR revealed TRPV1 expression in gills as well as spinal cord. Next, electrophysiological analyses of OmTRPV1 were performed using a two-electrode voltage-clamp technique with a Xenopus oocyte expression system. Heat stimulation evoked an inward current in heterologously expressed OmTRPV1. In addition, capsaicin produced current responses in OmTRPV1-expressing oocytes, but higher concentrations were needed for its activation compared to the mammalian orthologues. These results indicate that Om senses environmental stimuli (heat and capsaicin) through the activation of TRPV1, and this channel may play important roles in avoiding environments disadvantageous for survival in aquatic vertebrates. Highlights • Capsaicin evoked behavioral responses of Oncorhynchus masou ishikawae (Om).• The behavioral response to heat was potentiated by capsaicin.• Heterologously expressed OmTRPV1 was activated by heat and capsaicin.

SUBMITTER: Yoshimura A

PROVIDER: S-EPMC9309644 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:The maturation-inducing hormone 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP) was first identified in the amago salmon. However, although carbonyl reductase-like 20beta-hydroxysteroid dehydrogenase (CR/20beta-HSD) was reported to convert 17alpha-hydroxyprogesterone (17alpha-P) to DHP in rainbow trout, we previously found that CR/20beta-HSD mRNA was not up-regulated in stimulated granulosa cells from masu salmon, which suggests that DHP is synthesized by a different enzyme. Accordingly, the present study aimed to identify the specific 20beta-hydroxysteroid dehydrogenase (20beta-HSD) responsible for DHP production by granulosa cells during final oocyte maturation in masu salmon. Granulosa layers were isolated from ovarian follicles at one month before ovulation and incubated with or without forskolin, which was used to mimic luteinizing hormone. Subsequent RNA-sequencing yielded ~12 million reads, with an average length of 51 bp, and 71,062 contigs of >100 bp were constructed. Of the 953 contigs that were exclusively constructed from the reads of forskolin-induced granulosa layers, tBlastx analysis identified one contig (#f103496) that matched 17beta-hydroxysteroid dehydrogenase type 12. We found that mammalian cells transfected with full-length omhsd17beta12l exhibited considerable 20beta-HSD activity, as indicated by efficient conversion of exogenous 17alpha-P to DHP. In addition, we found that omhsd17beta12l mRNA levels were consistently low in follicles during vitellogenic growth; however, the levels increased significantly during final oocyte maturation. The levels of omhsd17beta12l mRNA were also considerably increased in granulosa layers in which 20beta-HSD activity was induced by salmon pituitary extract. Therefore, we suggest that omhsd17beta12l, not CR/20beta-HSD, is the 20beta-HSD responsible for DHP production by granulosa cells in masu salmon during final oocyte maturation. Comparison of mRNA levels between control and forskolin-incubated sample.

Dataset Information

Functional analysis of thermo-sensitive TRPV1 in an aquatic vertebrate, masu salmon (Oncorhynchus masou ishikawae)

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure