Differential expression of voltage-sensitive K+ and Ca2+ currents in neurons of the honeybee olfactory pathway

@article{citeulike:785031, abstract = {In order to understand the neuronal processes underlying olfactory learning, biophysical properties such as ion channel activity need to be analysed within neurons of the olfactory pathway. This study analyses voltage-sensitive ionic currents of cultured antennal lobe projection neurons and mushroom body Kenyon cells in the brain of the honeybee Apis mellifera. Rhodamine-labelled neurons were identified in vitro prior to recording, and whole-cell K+ and Ca2+ currents were measured. All neurons expressed transient and sustained outward K+ currents, but Kenyon cells expressed higher relative amounts of transient A-type K+ (IK,A) currents than sustained delayed rectifier K+ current (IK,V). The current density of the IK,V was significantly higher in projection neurons than in Kenyon cells. The voltage-dependency of K+ currents at positive membrane potentials was linear in Kenyon cells, but N-shaped in projection neurons. Blocking of voltage-sensitive Ca2+ currents transformed the N-shaped voltage-dependency into a linear one, indicating activation of calcium-dependent K+ currents (IK,Ca). The densities of currents through voltage-sensitive Ca2+ channels did not differ between the two neuron classes and the voltage-dependency of current activation was similar. Projection neurons thus express higher calcium-dependent K+ currents. These analyses revealed that the various neurons of the honeybee olfactory pathway in vitro have different current phenotypes, which may reflect functional differences between the neuron types in vivo. 10.1242/jeb.00053}, author = {Grunewald, Bernd }, citeulike-article-id = {785031}, doi = {http://dx.doi.org/10.1242/jeb.00053}, journal = {J Exp Biol}, keywords = {honeybee}, month = {January}, number = {1}, pages = {117--129}, posted-at = {2006-08-03 22:32:41}, priority = {2}, title = {Differential expression of voltage-sensitive K+ and Ca2+ currents in neurons of the honeybee olfactory pathway}, url = {http://dx.doi.org/10.1242/jeb.00053}, volume = {206}, year = {2003} }

TY - JOUR ID - citeulike:785031 L3 - citeulike-article-id:785031 TI - Differential expression of voltage-sensitive K+ and Ca2+ currents in neurons of the honeybee olfactory pathway JF - J Exp Biol VL - 206 IS - 1 SP - 117 EP - 129 N2 - In order to understand the neuronal processes underlying olfactory learning, biophysical properties such as ion channel activity need to be analysed within neurons of the olfactory pathway. This study analyses voltage-sensitive ionic currents of cultured antennal lobe projection neurons and mushroom body Kenyon cells in the brain of the honeybee Apis mellifera. Rhodamine-labelled neurons were identified in vitro prior to recording, and whole-cell K+ and Ca2+ currents were measured. All neurons expressed transient and sustained outward K+ currents, but Kenyon cells expressed higher relative amounts of transient A-type K+ (IK,A) currents than sustained delayed rectifier K+ current (IK,V). The current density of the IK,V was significantly higher in projection neurons than in Kenyon cells. The voltage-dependency of K+ currents at positive membrane potentials was linear in Kenyon cells, but N-shaped in projection neurons. Blocking of voltage-sensitive Ca2+ currents transformed the N-shaped voltage-dependency into a linear one, indicating activation of calcium-dependent K+ currents (IK,Ca). The densities of currents through voltage-sensitive Ca2+ channels did not differ between the two neuron classes and the voltage-dependency of current activation was similar. Projection neurons thus express higher calcium-dependent K+ currents. These analyses revealed that the various neurons of the honeybee olfactory pathway in vitro have different current phenotypes, which may reflect functional differences between the neuron types in vivo. 10.1242/jeb.00053 KW - honeybee AU - Grunewald, Bernd PY - 2003/01/01/ UR - http://dx.doi.org/10.1242/jeb.00053 ER -