AIM: Dopaminergic neurons in the substantia nigra pars compacta (SNc) play important roles in motor control and drug addiction. As the major afferent, GABAergic innervation controls the activity of SNc dopaminergic neurons. Although it is clear that nicotine modulates SNc dopaminergic neurons by activating subtypes of somatodendritic nicotinic acetylcholine receptors (nAChRs), the detailed mechanisms of this activation remain to be addressed. METHODS: In the current study, we recorded GABA(A) receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) from dissociated SNc dopaminergic neurons that were obtained using an enzyme-free procedure. These neurons preserved some functional terminals after isolation, including those that release GABA. RESULTS: We found that both extra- and intra-cellular calcium modulates sIPSCs in these neurons. Furthermore, both nicotine and endogenous acetylcholine enhance the frequency of sIPSCs. Moreover, endogenous acetylcholine tonically facilitates sIPSC frequency, primarily by activating the alpha4beta2* nAChRs on the GABAergic terminals. CONCLUSION: Nicotine facilitates GABA release onto SNc dopaminergic neurons mainly via the activation of presynaptic alpha4beta2* nAChRs.
AIM: Dopaminergic neurons in the substantia nigra pars compacta (SNc) play important roles in motor control and drug addiction. As the major afferent, GABAergic innervation controls the activity of SNc dopaminergic neurons. Although it is clear that nicotine modulates SNc dopaminergic neurons by activating subtypes of somatodendritic nicotinic acetylcholine receptors (nAChRs), the detailed mechanisms of this activation remain to be addressed. METHODS: In the current study, we recorded GABA(A) receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) from dissociated SNc dopaminergic neurons that were obtained using an enzyme-free procedure. These neurons preserved some functional terminals after isolation, including those that release GABA. RESULTS: We found that both extra- and intra-cellular calcium modulates sIPSCs in these neurons. Furthermore, both nicotine and endogenous acetylcholine enhance the frequency of sIPSCs. Moreover, endogenous acetylcholine tonically facilitates sIPSC frequency, primarily by activating the alpha4beta2* nAChRs on the GABAergic terminals. CONCLUSION:Nicotine facilitates GABA release onto SNc dopaminergic neurons mainly via the activation of presynaptic alpha4beta2* nAChRs.
Authors: Kechun Yang; Lori Buhlman; Ghous M Khan; Robert A Nichols; Guozhang Jin; J Michael McIntosh; Paul Whiteaker; Ronald J Lukas; Jie Wu Journal: J Neurosci Date: 2011-02-16 Impact factor: 6.167
Authors: Scott C Steffensen; Samuel I Shin; Ashley C Nelson; Stephanie S Pistorius; Stephanie B Williams; Taylor J Woodward; Hyun Jung Park; Lindsey Friend; Ming Gao; Fenfei Gao; Devin H Taylor; M Foster Olive; Jeffrey G Edwards; Sterling N Sudweeks; Lori M Buhlman; J Michael McIntosh; Jie Wu Journal: Addict Biol Date: 2017-09-13 Impact factor: 4.280