1. Younglim Lee, Stephanie Fitz, Phillip L Johnson and Anantha Shekhar
Repeated Stimulation of CRF Receptors in the BNST of Rats Selectively Induces Social but not Panic-Like Anxiety
Younglim Lee, Stephanie Fitz, Phillip L Johnson and Anantha Shekhar

2. Background
BNST identified as a key that relays and integrates limbic and autonomic info related to stress responses
CRF given centrally induces anxiogenic behaviors in different models:
EPM
Social Interaction (SI)
Open Field
Conflict Test
Acoustic Startle
Conditioned Fear Response
Both CRF1 & CRF2 receptors found in the BNST

3. Don't Do Drugs UCn1 = urocortin 1 – CRF agonist
CRF receptor 1 & 2 agonist (suggested CRF1 receptor)
Astressin – CRF antagonist – not receptor specific
mmol (mili mole) is 1 x 10-3 moles µmol (micro mole) is 1 x 10-6 moles nmol (nana mole) is 1 x 10-9 moles pmol (pica mole) is 1 x moles fmol (fempta mole) is 1 x moles

4. Previous Studies Found
Repeated priming injections into BLA w/ CRF receptor agonist Ucn1 at subthreshold dose induces long lasting behavioral change in SI & EPM
Ucn1 priming in BLA produced anxiety behaviors and physiological sensitivity to IV sodium lactate infusions as seen in panic & PTSD disorders

5. Sodium lactate given IV induces panic (Johnson et al. 2007)

6. Sodium lactate given IV induces panic (Johnson et al. 2007)

7. Hypothesis & Investigation
That acute stimulation of CRF receptors in BNST will anxiety & repeated stimulation will elicit persistent anxiety-like behaviors
Investigated
Effects of different UCn1 doses in BNST to determine subthreshold dose
Effects of repeated daily intra-BNST Ucn1 injections of found subthreshold dose (UCn1 priming)
Changes in lactate sensitivity following UCn1 priming of BNST

8. Animals Male Wistar Rats (275- 300g)
Individually housed at 22C, food/water ad libitum
12h light/dark, lights on at 0700h

9. Surgical Procedures Implantation of telemetry probes
Measuring
Arterial pressure
Heart rate
Femoral arterial line connected to telemetric probe
BNST cannulation
Only unilaterally

10. Behavior Tests Social Interaction (SI) EPM Anxiety test
Wooden box, place exp rat in with novel rat and video tape behavior
Grooming, sniffing, playful behavior
EPM

11. Exp. 1 -Injecting UCn1 in BNST (not adjacent area) will induce anxiety in rats measured in SI
Results
Fig a. suggest dose dependent reduction of SI following CRF receptor activation

12. Experiment 2
Repeated injections of UCn1 into BNST will lead to long-lasting anxiety

13. Exp. 2 Results
UCn1 of 6-fmol dose (subthreshold)

14. Exp. 2 Results cont.
No difference in EPM!

15. Experiment 3
Pretreatment w/ CRF antagonist will block development of Ucn1 priming in BNST
Rats injected locally w/ Astressin- a nonselective CRF antagonist prior to daily UCn1 dose (6-fmol)
Astressin- intransitive verb- (a \ˈstres\ inn)
Used colloquially in times of great stress
Example: I’m astressin OUT!!!

16. Exp. 3 results
Astressin completely blocked UCn1 priming in the BNST

17. Experiment 4
UCn1 priming of BNST will not increase sensitivity to a subsequent challenge w/ sodium lactate

18. Exp. 4 Timeline

19. Exp. 4 Results

20. Exp. 4 Results cont.
No change in SI or physiological responses w/ lactate infusion

21. Discussion UCn1 injected into BNST anxiety behavior
Suggests CRF system in BNST regulates certain anxiety behaviors
Decreases SI but no effect on EPM (only uni not bicannulated!)
BLA primed rats had anxiogenic effects in SI & EPM
UCn1 primed rats did not have panic-like cardiovascular responses to lactate infusion
BNST critical in acquisition/expression social anxiety w/0 the physiological sensitivity to lactate (Clinical Implications)

22. Discussion cont.
Authors note difference in SI for different strains of rats
Wistar: 15-35s
Sprague-Dawley: 40-70s
Long-Evans: ???
SI recorded in “light cycle” 9am-1pm
Acknowledge behavior test in dark cycle may increase SI

23. Discussion cont.
Drug seeking behavior modulated w/ CRF in BNST circuitry
Activation of CRF system for stress reinstatement of drug-seeking behavior
CRF receptor antagonism blocks this stress effect
BNST key to mediation
inject CRF drug-seeking
Inject CRF antagonist block drug-seeking behavior
Pathophysiology similar to many mental disorders

24. Discussion cont.
If social anxiety develops from CRF modulation in BNST
& If CRF stimulation w/in BNST modulates drug- seeking behavior
Then use UCn1 priming in BNST to search for vulnerability w/ substance abuse & psychiatric disorders

25. CRF1 & CRF2 Receptors
UCn1 & astressin high affinities for both CRF receptors
UCn1 in SI mediated CRF1 not CRF2 (Maybe? Prelim results)
Anxiogenic effects of CRF in BNST from CRF1 receptors
Drug-seeking from both CRF1 & CRF2

26. Take Home Repeated UCn1 priming into BNST = anxiety in SI but not EPM
Primed rats failed lactate challenge = no HR or pressure increases!
Priming may model social anxiety disorder!!!
Repeated activation of BNST CRFR!!!

27. The End