Transcript lecture notes

Testosterone
SONG
T is elevated during periods
of elevated aggression
T implant increases song rate
15.0
Songs / 10 min
12.5
10.0
7.5
5.0
2.5
0.0
control
testosterone
treatment
Hunt et al, 1997
T receptors found in song system
T is usually elevated during
periods of elevated aggression
Seasonal Changes in
Aggression, T and E2
?
Wingfield & Hahn, 1994
Block hormone synthesis or hormone receptor,
measure song
• Song Sparrows in Fall
• Treatment:
– Flutamide: blocks
androgen receptor
– ATD: blocks aromatase
• Test
– Play song on birds territory
to Simulate Territorial
Intrusion
– Measure Song production
in response
Soma et al, 1999
aromatase
Estrogen or Testosterone?
• Song Sparrows in Fall
• Treatment:
– Control (vehicles)
– Fadrazol: another aromatase
inhibitor
– Fadrazol + estrogen
• Rescue effect?
Soma et al, 2000
aromatase
+ E2
E2 receptors found in song system
Neurosteroid Hypothesis
• Steroid precursors released from adrenal or
gonad
• Made into active steroids in the brain
DHEA
Soma and Wingfield 2001
aromatase
Effects of DHEA?
HVC volume
Song production
DHEA
Soma et al, 2002, 2004
aromatase
Why Neurosteroids?
-DHEA is elevated in
spotted antbird
-DHEA increases
during aggressive
encounters