Psychopharmacology

, Volume 213, Issue 4, pp 697–706 | Cite as

Reduction of fear-potentiated startle by benzodiazepines in C57BL/6J mice

  • Kiersten S. Smith
  • Edward G. Meloni
  • Karyn M. Myers
  • Ashlee Van’t Veer
  • William A. CarlezonJr.
  • Uwe Rudolph
Original Investigation

Abstract

Rationale

Anxiety disorders affect 18% of the United States adult population annually. Recent surges in the diagnosis of posttraumatic stress disorder (PTSD) from combat-exposed veterans have prompted an urgent need to understand the pathophysiology underlying this debilitating condition.

Objectives

Anxiety and fear responses are partly modulated by gamma aminobutyric acid type A (GABAA) receptor-mediated synaptic inhibition; benzodiazepines potentiate GABAergic inhibition and are effective anxiolytics. Many genetically modified mouse lines are generated and/or maintained on the C57BL/6J background, a strain where manipulation of anxiety-like behavior using benzodiazepines is difficult. Fear-potentiated startle (FPS), a test of conditioned fear, is a useful preclinical tool to study PTSD-like responses but has been difficult to establish in C57BL/6J mice.

Methods

We modified several FPS experimental parameters and developed a paradigm to assess conditioned fear in C57BL/6J mice. The 6-day protocol consisted of three startle Acclimation days, a Pre-Test day followed by Training and Testing for FPS. Subject responses to the effects of three benzodiazepines were also examined.

Results

C57BL/6J mice had low levels of unconditioned fear assessed during Pre-Test (15–18%) but showed robust FPS (80–120%) during the Test session. Conditioned fear responses extinguished over repeated test sessions. Administration of the benzodiazepines alprazolam (0.5 and 1 mg/kg, i.p.), chlordiazepoxide (5 and 10 mg/kg, i.p.), and diazepam (1, 2, and 4 mg/kg, i.p.) significantly reduced FPS to Pre-Test levels.

Conclusions

We used a modified and pharmacologically-validated paradigm to assess FPS in mice thereby providing a powerful tool to examine the neurobiology of PTSD in genetic models of anxiety generated on the C57BL/6J background.

Keywords

Anxiety Benzodiazepine C57BL/6J mice Chlordiazepoxide Diazepam Fear-potentiated startle 

Notes

Acknowledgements

The project described was supported by a grant from the Andrew P. Merrill Memorial Fellowship Foundation and a fellowship from the National Institute of Neurological Disorders and Stroke Neuroscience Scholars Program to KSS, a Collaborative Initiative Award from the Howard Hughes Medical Institute to WAC, and Award Number R01 MH080006 from the National Institute of Mental Health to UR. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Mental Health or the National Institutes of Health.

Supplementary material

213_2010_2026_MOESM1_ESM.doc (279 kb)
ESM 1(DOC 279 kb)

References

  1. Baas JM, Grillon C, Bocker KB, Brack AA, Morgan CA 3rd, Kenemans JL, Verbaten MN (2002) Benzodiazepines have no effect on fear-potentiated startle in humans. Psychopharmacology 161:233–247CrossRefPubMedGoogle Scholar
  2. Bitsios P, Philpott A, Langley RW, Bradshaw CM, Szabadi E (1999) Comparison of the effects of diazepam on the fear-potentiated startle reflex and the fear-inhibited light reflex in man. J Psychopharmacol 13:226–234CrossRefPubMedGoogle Scholar
  3. Blanchard DC, Blanchard RJ (1972) Innate and conditioned reactions to threat in rats with amygdaloid lesions. J Comp Physiol Psychol 81:281–290CrossRefPubMedGoogle Scholar
  4. Bolles RC, Fanselow MS (1980) A perceptual-defense-recuperative model of fear and pain. Behav Brain Sci 3:291–323CrossRefGoogle Scholar
  5. Brown JS, Kalish HI, Farber IE (1951) Conditioned fear as revealed by the magnitude of startle response to an auditory stimulus. J Exp Psychol 41:317–327CrossRefPubMedGoogle Scholar
  6. Campeau S, Hayward MD, Hope BT, Rosen JB, Nestler EJ, Davis M (1991) Induction of the c-fos-proto-oncogene in rat amygdala during unconditioned fear and conditioned fear. Brain Res 565:349–352CrossRefPubMedGoogle Scholar
  7. Chabot CC, Taylor DH (1992) Daily rhythmicity of the rat acoustic startle response. Physiol Behav 51:885–889CrossRefPubMedGoogle Scholar
  8. Davis M (1974) Sensitization of the rat startle response by noise. J Comp Physiol Psychol 87:571–581CrossRefPubMedGoogle Scholar
  9. Davis M (1979) Diazepam and flurazepam: effects on conditioned fear as measured with the potentiated startle paradigm. Psychopharmacology 62:1–7CrossRefPubMedGoogle Scholar
  10. Davis M (2006) Neural systems involved in fear and anxiety measured with fear-potentiated startle. Am Psychol 61:741–756CrossRefPubMedGoogle Scholar
  11. Davis M, Astrachan DI (1978) Conditioned fear and startle magnitude: effects of different footshock or backshock intensities used during training. J Exp Psychol Anim Behav Process 4:95–103CrossRefPubMedGoogle Scholar
  12. Di Benedetto B, Kallnik M, Weisenhorn DM, Falls WA, Wurst W, Holter SM (2008) Activation of ERK/MAPK in the lateral amygdala of the mouse is required for acquisition of a fear-potentiated response. Neuropsychopharmacology 34:356–366CrossRefPubMedGoogle Scholar
  13. Falls WA (2002) Fear-potentiated startle in mice. Curr Prot Neurosci 8.11B.1–811B.16Google Scholar
  14. Falls WA, Carlson S, Turner G, Willott JF (1997) Fear-potentiated startle in two strains of inbred mice. Behav Neurosci 111:855–861CrossRefPubMedGoogle Scholar
  15. Falls WA, Fox JH, MacAulay CM (2010) Voluntary exercise improves both learning and consolidation of cued conditioned fear in C57 mice. Behav Brain Res 207:321–331CrossRefPubMedGoogle Scholar
  16. Fendt M, Burki H, Imobersteg S, Lingenhohl K, McAllister K, Orain D, Uzunov D, Chaperon F (2009) Fear-reducing effects of intra-amygdala neuropeptide Y infusion in animal models of conditioned fear: an NPY Y1 receptor independent effect. Psychopharmacology 206:291–301CrossRefPubMedGoogle Scholar
  17. Garakani A, Mathew SJ, Charney DS (2006) Neurobiology of anxiety disorders and implications for treatment. Mt Sinai J Med 73:941–949PubMedGoogle Scholar
  18. Grillon C (2002) Associative learning deficits increase symptoms of anxiety in humans. Biol Psychiatry 51:851–858CrossRefPubMedGoogle Scholar
  19. Grillon C, Ameli R, Woods SW, Merikangas K, Davis M (1991) Fear-potentiated startle in humans: effects of anticipatory anxiety on the acoustic blink reflex. Psychophysiology 25:588–595CrossRefGoogle Scholar
  20. Guscott MR, Cook GP, Bristow LJ (2000) Contextual fear conditioning and baseline startle responses in the rat fear-potentiated startle test: a comparison of benzodiazepine/gamma-aminobutyric acid-A receptor agonists. Behav Pharmacol 11:495–504PubMedGoogle Scholar
  21. Heldt S, Sundin V, Willott JF, Falls WA (2000) Posttraining lesions of the amygdala interfere with fear-potentiated startle to both visual and auditory conditioned stimuli in C57BL/6J mice. Behav Neurosci 114:749–759CrossRefPubMedGoogle Scholar
  22. Kallnik M, Elvert R, Ehrhardt N, Kissling D, Mahabir E, Welzl G, Faus-Kessler T, Hrabe de Angelis M, Wurst W, Schmidt J, Holter SM (2007) Impact of IVC housing on emotionality and fear learning in male C3HeB/FeJ and C57BL/6J mice. Mamm Genome 18:173–186CrossRefPubMedGoogle Scholar
  23. Kaplan HI, Sadock BJ, Grebb JA (1994) Synopsis of psychiatry, 7th edn. Williams and Wilkins, BaltimoreGoogle Scholar
  24. Kessler RC, Chiu WT, Demler O, Walters EE (2005) Prevalence, severity, and comorbidity of 12-month DSM-IV disorders in the national comorbidity survey replication. Arch Gen Psychiatry 62:617–627CrossRefPubMedGoogle Scholar
  25. Kilfoil T, Michel A, Montgomery D, Whiting RL (1989) Effects of anxiolytic and anxiogenic drugs on exploratory activity in a simple model of anxiety in mice. Neuropharmacology 28:901–905CrossRefPubMedGoogle Scholar
  26. Low K, Crestani F, Keist R, Benke D, Brunig I, Benson JA, Fritschy J-M, Rulicke T, Bluethmann H, Mohler H, Rudolph U (2000) Molecular and neuronal substrate for the selective attenuation of anxiety. Science 290:131–134CrossRefPubMedGoogle Scholar
  27. Mathiasen LS, Mirza NR, Rodgers RJ (2008) Strain- and model-dependent effects of chlordiazepoxide, L-838, 417 and zolpidem on anxiety-like behaviours in laboratory mice. Pharmacol Biochem Behav 90:19–36CrossRefPubMedGoogle Scholar
  28. Meloni EG, Davis M (1999) Muscimol in the deep layers of the superior colliculus/mesencephalic reticular formation blocks expression but not acquisition of fear-potentiated startle in rats. Behav Neurosci 113:1152–1160CrossRefPubMedGoogle Scholar
  29. Morgan CA 3rd, Grillon C, Southwick SM, Davis M, Charney DS (1995) Fear-potentiated startle in posttraumatic stress disorder. Biol Psychiatry 38:378–385CrossRefPubMedGoogle Scholar
  30. Myers KM, Davis M (2007) Mechanisms of fear extinction. Mol Psychiatry 12:120–150CrossRefPubMedGoogle Scholar
  31. National Research Council (1996) Guide for the care and use of laboratory animals. National Academy, WashingtonGoogle Scholar
  32. Quirk GJ, Mueller D (2008) Neural mechanisms of extinction learning and retrieval. Neuropsychopharmacology 33:56–72CrossRefPubMedGoogle Scholar
  33. Rescorla RA, Wagner AR (1972) A theory of Pavlovian conditioning: variations in the effectiveness of reinforcement and nonreinforcement. In: Black AH, Prokasy WF (eds) Classical conditioning II: current theory and research. Appleton-Century-Crofts, New York, pp 64–99Google Scholar
  34. Riba J, Rodriguez-Fornells A, Urbano G, Morte A, Antonijoan R, Barbanoj MJ (2001) Differential effects of alprazolam on the baseline and fear-potentiated startle reflex in humans: a dose-response study. Psychopharmacology 157:358–367CrossRefPubMedGoogle Scholar
  35. Risbrough VB, Brodkin JD, Geyer MA (2003) GABA-A and 5HT1A receptor agonists block expression of fear-potentiated startle in mice. Neuropsychopharmacology 25:654–663CrossRefGoogle Scholar
  36. Risbrough VB, Geyer MA, Hauger RL, Coste S, Stenzel-Poore M, Wurst W, Holsboer F (2009) CRF1 and CRF2 receptors are required for potentiated startle to contextual but not discrete cues. Neuropsychopharmacology 34:1494–1503CrossRefPubMedGoogle Scholar
  37. Rodriguez-Fornells A, Riba J, Gironell A, Kulisevsky J, Barbanoj MJ (1999) Effects of alprazolam on the acoustic startle response in humans. Psychopharmacology 143:280–285CrossRefPubMedGoogle Scholar
  38. Rudolph U, Crestani F, Benke D, Brunig I, Benson JA, Fritschy J-M, Martin JR, Bluethmann H, Mohler H (1999) Benzodiazepine actions mediated by specific gamma-aminobutyric acidA receptor subtypes. Nature 401:796–800CrossRefPubMedGoogle Scholar
  39. Shader RI, Greenblatt DJ (1993) Use of benzodiazepines in anxiety disorders. N Engl J Med 328:1398–1405CrossRefPubMedGoogle Scholar
  40. Smith TC, Ryan MAK, Wingard DL, Slymen DJ, Sallis JF, Kritz-Silverstein D (2008) New onset and persistent symptoms of post-traumatic stress disorder self reported after deployment and combat exposures: prospective population based US military cohort study. Br Med J 336:366–371CrossRefGoogle Scholar
  41. Straub CJ, Carlezon WA Jr, Rudolph U (2010) Diazepam and cocaine potentiate brain stimulation reward in C57BL/6J mice. Behav Brain Res 206:17–20Google Scholar
  42. Trevor AJ, Way WL (1987) Sedative-Hypnotics. In: Katzung BG (ed) Basic and clinical pharmacology, 3rd edn. Appleton and Lange, Norwalk, pp 241–253Google Scholar
  43. Waddell J, Dunnett C, Falls WA (2004) C57BL/6J and DBA/2J mice differ in extinction and renewal of extinguished conditioned fear. Behav Brain Res 154:567–576CrossRefPubMedGoogle Scholar
  44. Walker DL, Davis M (1997) Anxiogenic effects of high illumination levels assessed with the acoustic startle paradigm. Biol Psychiatry 42:461–471CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Kiersten S. Smith
    • 1
  • Edward G. Meloni
    • 1
  • Karyn M. Myers
    • 1
  • Ashlee Van’t Veer
    • 1
  • William A. CarlezonJr.
    • 1
  • Uwe Rudolph
    • 1
  1. 1.Department of PsychiatryMcLean Hospital and Harvard Medical SchoolBelmontUSA

Personalised recommendations