Presynaptic Regulation of Tonic Inhibition by Neuromodulatory Transmitters in the Basal Amygdala


Tonic inhibition mediated by ambient levels of GABA that activate extrasynaptic GABAA receptors emerges as an essential factor that tunes neuronal network excitability in vitro and shapes behavioral responses in vivo. To address the role of neuromodulatory transmitter systems on this type of inhibition, we employed patch clamp recordings in mouse amygdala slice preparations. Our results show that the current amplitude of tonic inhibition (Itonic) in projection neurons of the basal amygdala (BA) is increased by preincubation with the neurosteroid THDOC, while the benzodiazepine diazepam is ineffective. This suggests involvement of THDOC sensitive δ subunit containing GABAA receptors in mediating tonic inhibition. Moreover, we provide evidence that the neuromodulatory transmitters NE, 5HT, and ACh strongly enhance spontaneous IPSCs as well as Itonic in the BA. As the increase in frequency, amplitude, and charge of sIPSCs by these neuromodulatory transmitters strongly correlated with the amplitude of Itonic, we conclude that spill-over of synaptic GABA leads to activation of Itonic and thereby to dampening of amygdala excitability. Since local injection of THDOC, as a positive modulator of tonic inhibition, into the BA interfered with the expression of contextual fear memory, our results point to a prominent role of Itonic in fear learning.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8


  1. 1.

    Asan E (1998) The catecholaminergic innervation of the rat amygdala. Adv Anat Embryol Cell Biol 142:1–118

    CAS  Article  Google Scholar 

  2. 2.

    Asan E, Steinke M, Lesch KP (2013) Serotonergic innervation of the amygdala: targets, receptors, and implications for stress and anxiety. Histochem Cell Biol 139:785–813

    CAS  Article  Google Scholar 

  3. 3.

    Bocchio M, McHugh SB, Bannerman DM, Sharp T, Capogna M (2016) Serotonin, amygdala and fear: assembling the puzzle. Front Neural Circuits 10:24

    Article  Google Scholar 

  4. 4.

    Botta P, Demmou L, Kasugai Y, Markovic M, Xu C, Fadok JP, Lu T, Poe MM et al (2015) Regulating anxiety with extrasynaptic inhibition. Nat Neurosci 18:1493–1500

    CAS  Article  Google Scholar 

  5. 5.

    Braga MF, Aroniadou-Anderjaska V, Manion ST, Hough CJ, Li H (2004) Stress impairs alpha(1A) adrenoceptor-mediated noradrenergic facilitation of GABAergic transmission in the basolateral amygdala. Neuropsychopharmacology 29:45–58

    CAS  Article  Google Scholar 

  6. 6.

    Bright DP, Aller MI, Brickley SG (2007) Synaptic release generates a tonic GABA(A) receptor-mediated conductance that modulates burst precision in thalamic relay neurons. J Neurosci 27:2560–2569

    CAS  Article  Google Scholar 

  7. 7.

    Connelly WM, Errington AC, Di Giovanni G, Crunelli V (2013) Metabotropic regulation of extrasynaptic GABAA receptors. Front Neural Circuits 7:171

    Article  Google Scholar 

  8. 8.

    Crunelli V, Di Giovanni G (2014) Monoamine modulation of tonic GABAA inhibition. Rev Neurosci 25:195–206

    CAS  Article  Google Scholar 

  9. 9.

    Ehrlich I, Humeau Y, Grenier F, Ciocchi S, Herry C, Lüthi A (2009) Amygdala inhibitory circuits and the control of fear memory. Neuron 62:757–771

    CAS  Article  Google Scholar 

  10. 10.

    Fujimura J, Nagano M, Suzuki H (2005) Differential expression of GABA(A) receptor subunits in the distinct nuclei of the rat amygdala. Brain Res Mol Brain Res 138:17–23

    CAS  Article  Google Scholar 

  11. 11.

    Galvez R, Mesches MH, McGaugh JL (1996) Norepinephrine release in the amygdala in response to footshock stimulation. Neurobiol Learn Mem 66:253–257

    CAS  Article  Google Scholar 

  12. 12.

    Glykys J, Mody I (2007) Activation of GABAA receptors: views from outside the synaptic cleft. Neuron 56:763–770

    CAS  Article  Google Scholar 

  13. 13.

    Herman MA, Contet C, Justice NJ, Vale W, Roberto M (2013) Novel subunit-specific tonic GABA currents and differential effects of ethanol in the central amygdala of CRF receptor-1 reporter mice. J Neurosci 33:3284–3298

    CAS  Article  Google Scholar 

  14. 14.

    Herman MA, Contet C, Roberto M (2016) A functional switch in tonic GABA currents alters the output of central amygdala corticotropin releasing factor receptor-1 neurons following chronic ethanol exposure. J Neurosci 36:10729–10741

    CAS  Article  Google Scholar 

  15. 15.

    Hörtnagl H, Tasan RO, Wieselthaler A, Kirchmair E, Sieghart W, Sperk G (2013) Patterns of mRNA and protein expression for 12 GABAA receptor subunits in the mouse brain. Neuroscience 236:345–372

    Article  Google Scholar 

  16. 16.

    Jang HJ, Cho KH, Joo K, Kim MJ, Rhie DJ (2015) Differential modulation of phasic and tonic inhibition underlies serotonergic suppression of long-term potentiation in the rat visual cortex. Neuroscience 301:351–362

    CAS  Article  Google Scholar 

  17. 17.

    Jiang X, Xing G, Yang C, Verma A, Zhang L, Li H (2009) Stress impairs 5-HT2A receptor-mediated serotonergic facilitation of GABA release in juvenile rat basolateral amygdala. Neuropsychopharmacology 34:410–423

    CAS  Article  Google Scholar 

  18. 18.

    Jiang L, Kundu S, Lederman JD, López-Hernández GY, Ballinger EC, Wang S, Talmage DA Role LW (2016) Cholinergic signaling controls conditioned fear behaviors and enhances plasticity of cortical-amygdala circuits. Neuron 90:1057–1070

    CAS  Article  Google Scholar 

  19. 19.

    Kaneko K, Tamamaki N, Owada H, Kakizaki T, Kume N, Totsuka M, Yamamoto T, Yawo H et al (2008) Noradrenergic excitation of a subpopulation of GABAergic cells in the basolateral amygdala via both activation of nonselective cationic conductance and suppression of resting K+ conductance: a study using glutamate decarboxylase 67-green fluorescent protein knock-in mice. Neuroscience 157:781–797

    CAS  Article  Google Scholar 

  20. 20.

    Krall J, Balle T, Krogsgaard-Larsen N, Sørensen TE, Krogsgaard-Larsen P, Kristiansen U, Frølund B (2015) GABAA receptor partial agonists and antagonists: structure, binding mode, and pharmacology. Adv Pharmacol 72:201–227

    Article  Google Scholar 

  21. 21.

    Kulisch C, Eckers N, Albrecht D (2011) Method of euthanasia affects amygdala plasticity in horizontal brain slices from mice. J Neurosci Methods 201:340–345

    CAS  Article  Google Scholar 

  22. 22.

    Lee V, Maguire J (2014) The impact of tonic GABAA receptor-mediated inhibition on neuronal excitability varies across brain region and cell type. Front Neural Circuits 8:3

    Article  Google Scholar 

  23. 23.

    Li R, Nishijo H, Ono T, Ohtani Y, Ohtani O (2002) Synapses on GABAergic neurons in the basolateral nucleus of the rat amygdala: double-labeling immunoelectron microscopy. Synapse 43:42–50

    CAS  Article  Google Scholar 

  24. 24.

    Lindemeyer AK, Liang J, Marty VN, Meyer EM, Suryanarayanan A, Olsen RW, Spigelman I (2014) Ethanol-induced plasticity of GABAA receptors in the basolateral amygdala. Neurochem Res 39:1162–1170

    CAS  Article  Google Scholar 

  25. 25.

    Liu ZP, Song C, Wang M, He Y, Xu XB, Pan HQ, Chen WB, Peng WJ et al (2014) Chronic stress impairs GABAergic control of amygdala through suppressing the tonic GABAA receptor currents. Mol Brain 7:32

    Article  Google Scholar 

  26. 26.

    Liu ZP, He QH, Pan HQ, Xu XB, Chen WB, He Y, Zhou J, Zhang WH et al (2016) Delta Subunit-Containing Gamma-Aminobutyric Acid a receptor disinhibits lateral amygdala and facilitates fear expression in mice. Biol Psychiatry pii S0006-3223:32539–32532

    Google Scholar 

  27. 27.

    Marowsky A, Rudolph U, Fritschy JM, Arand M (2012) Tonic inhibition in principal cells of the amygdala: a central role for α3 subunit-containing GABAA receptors. J Neurosci 32:8611–8619

    CAS  Article  Google Scholar 

  28. 28.

    Marowsky A, Vogt KE (2014) Delta-subunit-containing GABAA-receptors mediate tonic inhibition in paracapsular cells of the mouse amygdala. Front Neural Circuits 8:27

    Article  Google Scholar 

  29. 29.

    Martin BS, Corbin JG, Huntsman MM (2014) Deficient tonic GABAergic conductance and synaptic balance in the fragile X syndrome amygdala. J Neurophysiol 112:890–902

    CAS  Article  Google Scholar 

  30. 30.

    Meis S, Stork O, Munsch T (2011) Neuropeptide S-mediated facilitation of synaptic transmission enforces subthreshold theta oscillations within the lateral amygdala. PLoS One 6:e18020

    CAS  Article  Google Scholar 

  31. 31.

    Miyajima M, Ozaki M, Wada K, Sekiguchi M (2010) Noradrenaline-induced spontaneous inhibitory postsynaptic currents in mouse basolateral nucleus of amygdala pyramidal neurons: Comparison with dopamine-induced currents. Neurosci Lett 480:167–172

    CAS  Article  Google Scholar 

  32. 32.

    Muller JF, Mascagni F, McDonald AJ (2007) Serotonin-immunoreactive axon terminals innervate pyramidal cells and interneurons in the rat basolateral amygdala. J Comp Neurol 505:314–335

    Article  Google Scholar 

  33. 33.

    Muller JF, Mascagni F, McDonald AJ (2011) Cholinergic innervation of pyramidal cells and parvalbumin-immunoreactive interneurons in the rat basolateral amygdala. J Comp Neurol 519:790–805

    Article  Google Scholar 

  34. 34.

    Nimitvilai S, Lopez MF, Mulholland PJ, Woodward JJ (2017) Ethanol dependence abolishes monoamine and GIRK (Kir3) channel inhibition of orbitofrontal cortex excitability. Neuropsychopharmacology 42:1800–1812.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  35. 35.

    Olmos-Serrano JL, Paluszkiewicz SM, Martin BS, Kaufmann WE, Corbin JG, Huntsman MM (2010) Defective GABAergic neurotransmission and pharmacological rescue of neuronal hyperexcitability in the amygdala in a mouse model of fragile X syndrome. J Neurosci 30:9929–9938

    CAS  Article  Google Scholar 

  36. 36.

    Pape HC, Pare D (2010) Plastic synaptic networks of the amygdala for the acquisition, expression, and extinction of conditioned fear. Physiol Rev 90:419–463

    CAS  Article  Google Scholar 

  37. 37.

    Phelps EA, LeDoux JE (2005) Contributions of the amygdala to emotion processing: from animal models to human behavior. Neuron 48:175–187

    CAS  Article  Google Scholar 

  38. 38.

    Pidoplichko VI, Prager EM, Aroniadou-Anderjaska V, Braga MF (2013) α7-Containing nicotinic acetylcholine receptors on interneurons of the basolateral amygdala and their role in the regulation of the network excitability. J Neurophysiol 110:2358–2369

    CAS  Article  Google Scholar 

  39. 39.

    Pirker S, Schwarzer C, Wieselthaler A, Sieghart W, Sperk G (2000) GABA(A) receptors: immunocytochemical distribution of 13 subunits in the adult rat brain. Neuroscience 101:815–850

    CAS  Article  Google Scholar 

  40. 40.

    Quirk GJ, Gehlert DR (2003) Inhibition of the amygdala: key to pathological states? Ann N Y Acad Sci 985:263–272

    CAS  Article  Google Scholar 

  41. 41.

    Rainnie DG (1999) Serotonergic modulation of neurotransmission in the rat basolateral amygdala. J Neurophysiol 82:69–85

    CAS  Article  Google Scholar 

  42. 42.

    Rombo DM, Dias RB, Duarte ST, Ribeiro JA, Lamsa KP, Sebastião AM (2016) Adenosine A1 receptor suppresses tonic GABAA receptor currents in hippocampal pyramidal cells and in a defined subpopulation of interneurons. Cereb Cortex 26:1081–1095

    Article  Google Scholar 

  43. 43.

    Romo-Parra H, Blaesse P, Sosulina L, Pape HC (2015) Neurosteroids increase tonic GABAergic inhibition in the lateral section of the central amygdala in mice. J Neurophysiol 113:3421–3343

    CAS  Article  Google Scholar 

  44. 44.

    Sara SJ, Bouret S (2012) Orienting and reorienting: the locus coeruleus mediates cognition through arousal. Neuron 76:130–141

    CAS  Article  Google Scholar 

  45. 45.

    Skelly MJ, Ariwodola OJ, Weiner JL (2017) Fear conditioning selectively disrupts noradrenergic facilitation of GABAergic inhibition in the basolateral amygdala. Neuropharmacology 113:231–240

    CAS  Article  Google Scholar 

  46. 46.

    Smith SS (2013) α4βδ GABAA receptors and tonic inhibitory current during adolescence: effects on mood and synaptic plasticity. Front Neural Circuits 7:135

    PubMed  PubMed Central  Google Scholar 

  47. 47.

    Unal CT, Pare D, Zaborszky L (2015) Impact of basal forebrain cholinergic inputs on basolateral amygdala neurons. J Neurosci 35:853–863

    Article  Google Scholar 

  48. 48.

    Uusi-Oukari M, Korpi ER (2010) Regulation of GABA(A) receptor subunit expression by pharmacological agents. Pharmacol Rev 62:97–135

    CAS  Article  Google Scholar 

  49. 49.

    Vicini S, Ferguson C, Prybylowski K, Kralic J, Morrow AL, Homanics GE (2001) GABA(A) receptor alpha1 subunit deletion prevents developmental changes of inhibitory synaptic currents in cerebellar neurons. J Neurosci 21:3009–3016

    CAS  Article  Google Scholar 

  50. 50.

    Viviani D, Terrettaz T, Magara F, Stoop R (2010) Oxytocin enhances the inhibitory effects of diazepam in the rat central medial amygdala. Neuropharmacology 58:62–68

    CAS  Article  Google Scholar 

  51. 51.

    Whissell PD, Lecker I, Wang DS, Yu J, Orser BA (2015) Altered expression of δGABAA receptors in health and disease. Neuropharmacology 88:24–35

    CAS  Article  Google Scholar 

  52. 52.

    Wilson MA, Fadel JR (2017) Cholinergic regulation of fear learning and extinction. J Neurosci Res 95:836–852

    CAS  Article  Google Scholar 

  53. 53.

    Wu LJ, Ko SW, Toyoda H, Zhao MG, Xu H, Vadakkan KI, Ren M, Knifed E et al (2007) Increased anxiety-like behavior and enhanced synaptic efficacy in the amygdala of GluR5 knockout mice. PLoS One 2:e167

    Article  Google Scholar 

  54. 54.

    Zhang J, Muller JF, McDonald AJ (2013) Noradrenergic innervation of pyramidal cells in the rat basolateral amygdala. Neuroscience 228:395–408

    CAS  Article  Google Scholar 

  55. 55.

    Zhu PJ, Stewart RR, McIntosh JM, Weight FF (2005) Activation of nicotinic acetylcholine receptors increases the frequency of spontaneous GABAergic IPSCs in rat basolateral amygdala neurons. J Neurophysiol 94:3081–3091

    CAS  Article  Google Scholar 

Download references


We thank Kathrin Friese, Colette Obst, Regina Ziegler, and Evelyn Friedl for excellent technical assistance.


Funding was provided by the Deutsche Forschungsgemeinschaft (SFB 779, TP B6) and by the EU Joint Programme-Neurodegenerative Disease Research (JPND) project CIRCPROT (jointly funded by BMBF and EU Horizon 2020 grant agreement No 643417).

Author information



Corresponding authors

Correspondence to S. Meis or V. Lessmann.

Ethics declarations

Conflict of Interest

The authors declare that they have no conflict of interest.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Meis, S., Endres, T., Munsch, T. et al. Presynaptic Regulation of Tonic Inhibition by Neuromodulatory Transmitters in the Basal Amygdala. Mol Neurobiol 55, 8509–8521 (2018).

Download citation


  • Amygdala
  • Tonic inhibition
  • GABA
  • Norepinephrine
  • Nicotine
  • 5HT