Expts
A list of experiments in progress :
2/17/07 Up-Down magnet exposure (Expt PK)
Smith, Ortega, Janowitz, Muller. To test the effects of combining head-up exposure and head-down exposure (i.e. does combined exposure cancel out magnet effects?). After 10 days on water restriction, female rats (n= 24) will get 10-min acccess to 0.125% saccharin and then be exposed to 14.1T or sham exposed. There are 5 groups: Group MUD (n=4) will be placed in the magnet head-up for 15 min, removed, and put back in the magnet for 15 min head down. Group MDU (n=4) will be placed in the magnet head-down for 15 min, removed, and put back in the magnet for 15 min head up. Two control groups (SUD and SDU, n=4 each) will be sham-exposed in parallel to groups MUD and MDU. As a positive control, rats in group MUU (n= 8) will be placed in the magnet head up for 15 min, removed, and placed back in the magnet head-up again for another 15 min. Water restriction began on 2-17-07; conditioning day will be 2-28-07.
2/17/07 More one-day adaptation to magnet exposure (Expt PJ)
Smith, Ortega, Janowitz, Muller. Follow-up experiment to Expt PH. After 10 days on water restriction, female rats are exposed 3 times for 30 min all on the same day; the last exposure is paired with 10min access to 0.125% saccharin. There are 3 groups, n=4/group. Group MMM gets 2x30min 14.1T exposure, then saccharin paired with 30 min at 14.1T. Group SSM gets 2x30min of sham exposure, then saccharin paired with 30 min at 14.1T. Group SSS ets 2x30min of sham exposure, then saccharin paired with 30 min sham exposure. All rats videotaped for 2 min after all exposures. Day after conditioning, 2-bottle preference tests begin. Water restriction began on 2-17-07; conditioning day will be 2-27-07.
1/25/07 Serine Racemase and NR2B in situ hybridization
Davenport. Pilot examination of SR and NR2B mRNA expression in gustatory cortex and amygdala. One rat given ~16-h access to 0.125% saccharin, control rat just water. Results: Serine Racemase worked great, NR2B showed no label at all. No aspparente effect of saccharin access. Follow-up: Will examine effects of NMDA drug treatments on serine racemase expression, and try relabeling NR probe.
1/15/07 Extinction of saccharin and NaCl-LiCl CTA in female rats (Expt PI)
Smith, Ortega, Janowitz, Muller. Folow-up experiment to "stacked rats" paper, as suggested by reviewer. After saccharin-magnet pairing, CTA in female rats does not readily extinguish. This expt tests 2 different CS's (saccharin vs. NaCl) using a different US (LiCl). Female rats (n=32) will be conditioned against either 0.125% saccharin or 0.45% NaCl (10 min access) paired with LiCl (12 ml/kg) immediately after CS. Results: both LiCl treated groups showed a significant aversion, but there was no apparent extinction in either group.
1/8/07 Sucrose/NaCl CTA two-bottle discrimination (Expt SO)
Ortega. Follow-up experiment to experiment SN, which is follow-up to Howard's taste specificity in short-term CTA. Male rats (n=12) will be conditioned against 5% sucrose or 75 mM NaCl paired with LiCl (12 ml/kg) immediately after access, then given two bottle preference tests: Sucr vs NaCl, Sucr vs water, and NaCl vs water. Results: Rats showed clear discrimination such that CS- was preferred over CS+ and water for both sucrose and NaCl. There was a funny order effect in Sucrose CTA rats, however, in that if first tested with Sucr vs NaCl (i.e. before a sucrose v water and NaCl v water tests), the Sucrose CTA rats did not drink either sucrose or NaCl.
1/5/07 GLP-1 and Serine Racemase RT-PCR
Davenport, Ortega. From male sprague-dawley rat, dissected gustatory cortex, cerebellum, hypothalamus, amygdala, and hippocampus/cortex for RNA extraction by Trizol. Will perform RT-PCR for serine racemase (RD) and GLP-1R receptors (BO). Results: The serine racemase Rt-PCR worked great, the GLP-1R did not. Will redesign the primers for future experiment.
12/06-2/07 c-Fos induction after Conditioned Flavor-Taste Preference Expression
Golden, Ortega, Kwon (taught COC). Rats given a CFTP by several days of 24-h access to kool-aid, alternating solutions in high concentration saccharin (preferred, CS+/US+) or low concentration of saccharin (non-preferred, CS+/US-.) CFTP is tested by 24-h 2-bottle preference between CS+/US- vs CS-/US-. Intraoral catheters were implanted. After 3 days of water infusions, rats were infused (10 ml /10 min)with either US-, US+, CS+/US-, or CS-/US-. One hour later, rats were prefused. Olfactory bulb, gustatory cortex, amygdala, PBN, and NTS were processed for c-Fos.
11/06-2/07 Swimming in Circles induced by Magnetic Field Exposure in Mice
CE Houpt, Smith (asst by Ortega, Janowitz, Muller) Male mice (C57/BlJ) were restrained and exposed 3 at a time to 14.1 T magnetic field for 30-min, or sham-exposed. Mice were then placed in center of a 2-m diameter swimming pool for a 2-min swim test. Magnet and sham-exposed mice were tested 0, 10, or 20 min after the end of restraint. Magnet-exposed mice and 0-min sham-exposed mice were retested at 24-h to detect persistent deficits in swimming. CEH working on Mac application to quantify rotation of mice from quicktime video.