Hi

I apply nicotine by pressure directly in the neuron and there is some good excitatory response; I try to see the inversion potential for this current so I changed the membrane potential from -70mV to +70mV step by step (-70, -50, -30, 0, +30, +70) and at -70mV there is not response anymore, and keep so for +30 anf +70. Most of this current is suppose to by for Na+. The question is why this current dont become inverted in +70?

Thanks.

"Rectification" my friend. Nicotinic acetylcholine receptors rectify.

Just some selected references

http://www.ncbi.nlm.nih.gov/pubmed/16825297?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum

http://www.ncbi.nlm.nih.gov/pubmed/14614969?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum

http://www.ncbi.nlm.nih.gov/pubmed/12742634?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum

http://www.ncbi.nlm.nih.gov/pubmed/9495824?ordinalpos=19&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum