14 research outputs found
Steroid receptor expression in the fish inner ear varies with sex, social status, and reproductive state
<p>Abstract</p> <p>Background</p> <p>Gonadal and stress-related steroid hormones are known to influence auditory function across vertebrates but the cellular and molecular mechanisms responsible for steroid-mediated auditory plasticity at the level of the inner ear remain unknown. The presence of steroid receptors in the ear suggests a direct pathway for hormones to act on the peripheral auditory system, but little is known about which receptors are expressed in the ear or whether their expression levels change with internal physiological state or external social cues. We used qRT-PCR to measure mRNA expression levels of multiple steroid receptor subtypes (estrogen receptors: ERα, ERβa, ERβb; androgen receptors: ARα, ARβ; corticosteroid receptors: GR2, GR1a/b, MR) and aromatase in the main hearing organ of the inner ear (saccule) in the highly social African cichlid fish <it>Astatotilapia burtoni</it>, and tested whether these receptor levels were correlated with circulating steroid concentrations.</p> <p>Results</p> <p>We show that multiple steroid receptor subtypes are expressed within the main hearing organ of a single vertebrate species, and that expression levels differ between the sexes. We also show that steroid receptor subtype-specific changes in mRNA expression are associated with reproductive phase in females and social status in males. Sex-steroid receptor mRNA levels were negatively correlated with circulating estradiol and androgens in both males and females, suggesting possible ligand down-regulation of receptors in the inner ear. In contrast, saccular changes in corticosteroid receptor mRNA levels were not related to serum cortisol levels. Circulating steroid levels and receptor subtype mRNA levels were not as tightly correlated in males as compared to females, suggesting different regulatory mechanisms between sexes.</p> <p>Conclusions</p> <p>This is the most comprehensive study of sex-, social-, and reproductive-related steroid receptor mRNA expression in the peripheral auditory system of any single vertebrate. Our data suggest that changes in steroid receptor mRNA expression in the inner ear could be a regulatory mechanism for physiological state-dependent auditory plasticity across vertebrates.</p
Effects of the Menstrual Cycle and Oral Contraception on Singers' Pitch Control
Purpose: Difficulties with intonation and vibrato control
during the menstrual cycle have been reported by singers;
however, this phenomenon has not yet been systematically
investigated.
Method: A double-blind randomized placebo-controlled trial
assessing effects of the menstrual cycle and use of a combined oral
contraceptive pill (OCP) on pitch control in singing is presented.
Audio-electrolaryngograph recordings were made and blood
samples were taken from 9 singers in each of the 3 phases of the
menstrual cycle both under the placebo and the OCP conditions
for a total of 6 months. Participants sang an exercise consisting
of an ascending octave followed by a descending major triad,
starting on pitches F4 and B4. Pitch control was assessed in terms
of the octave’s deviations from pure intonation and of the vibrato
rate and extent.
Results: Significant differences were found between the 3 phases
of the cycle regarding octave size only for pitch F5 during OCP
use. Significant vibrato rate differences between placebo and
OCP conditions were found only for pitch F5.
Conclusion: OCP use may have an effect on pitch control in
singers. Possible explanations point to a complex interaction
between hormonal milieu and pitch control, enhancing the
need for longitudinal studies