[Abstract Title]. - Society for Neuroscience

we investigated the effects of the intranasal administration of testosterone on the activity of
dopaminergic and serotonergic neurons in the brain, and compared the effects to the systemic
testosterone administration. Male Wistar rats were implanted with guide cannulae at the dorsal
border of the neostriatum and nucleus accumbens. Three to 5 days later, they were anesthetized
with urethane and microdialysis probes were inserted. After a stabilization period of 2 hours,
four baseline samples were collected. Thereafter, the treatment (vehicle, composed of a viscous
castor oil mixture (M et P Pharma AG, Stans, Switzerland; 0.5, 1.0 or 2.0 mg/kg of testosterone)
was applied (5µl in each nostril). In other animals, a subcutaneous injection of testosterone (2.0,
4.0 or 8.0 mg/kg) or vehicle (sesame oil) was given. Samples were collected at 30-min intervals
for 5 h and analyzed by high performance liquid chromatography. Intranasal administration of
testosterone significantly increased dopamine (DA) and serotonin (5-HT) levels in the
neostriatum and nucleus accumbens. In the neostriatum, an immediate and gradual increase of
DA occurred after the 2mg/kg dose, while a significant increase in 5-HT levels was seen after the
1mg/kg dose. In the nucleus accumbens, DA and 5-HT significantly increased after, both, the
1mg/kg and 2mg/kg doses. Subcutaneous administration of testosterone (8mg/kg) caused
significant increases of DA and 5-HT in the neostriatum. No significant effect was seen in the
nucleus accumbens after systemic administration. We conclude that the intranasal administration
of testosterone has immediate effects on the dopaminergic and serotonergic neurotransmission
and is an efficacious way for targeting the brain.
Disclosures: J.P. Huston , None; M.A. de Souza Silva, None; B. Topic, None; C. Mattern,
None.
Poster
273. Basal Ganglia: Transmitters and Neuromodulation I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 273.8/II23
Topic: D.15.a. Transmitters and neuromodulation
Support: UPHS NIH NS-23805
UPHS NIH DA-020654
Title: The ventromedial tegmental nucleus: a potent contributor to the circuitry of the
mesopontine tegmentum and likely modulator of multiple ascending neuromodulatory pathways,
that is targeted by robust outputs from the lateral habenula
Authors: *D. S. ZAHM 1 , T. C. JHOU 2 , S. GEISLER 3 , M. MARINELLI 4 ;
1 Dept Pharmacol & Physiol Sci., St Louis Univ. Sch. Med., St. Louis, MO; 2 Dept. of