Transforming growth factor-beta2 selectively alters the developmental expression of the fast transient A-current in cultured rat superior cervical ganglion neurons.
Cultures of neonatal rat superior cervical ganglion (SCG) were utilized to examine the ability of transforming growth factor-beta2 (TGFbeta2) to alter voltage-gated K+ channel development. Whole-cell patch clamp recordings were used to monitor changes in three separate K+ currents: A rapidly inactivating A-current (I(Af)), a slowly inactivating A-current (I(As)), and a non-inactivating current (I(K)). Continuous TGFbeta2 (10 ng/ml) treatment selectively altered the normal developmental decrease in I(Af) expression in SCG neurons, but did not significantly change I(As) or I(K) expression. After 2 weeks of treatment, the mean I(Af) current density in control cultures had decreased 67%, while the I(Af) current density in TGFbeta2 treated cultures remained near initial values (approximately 2.7-fold higher than control). This difference remained even after 4 weeks of exposure. TGFbeta2 did not appear to change the activation kinetics or voltage-dependence of I(Af). These findings indicate that TGFbeta2 may play an important role in modulating the development of neuronal excitability by regulating the expression of voltage-gated K+ channels.
Phelan
K D
KD
Department of Anatomy, University of Arkansas for Medical Sciences, Little Rock 72205-7199, USA. PHELANKEVIND@EXCHANGE.UAMS.EDU
Chang
J Y
JY
Kane
C J
CJ
D000818:Animals; D002478:Cells, Cultured; D004558:Electric Stimulation; D004594:Electrophysiology; D015640:Ion Channel Gating / Q000187:drug effects*; D007700:Kinetics; D009474:Neurons / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D015221:Potassium Channels / Q000096:biosynthesis / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017783:Superior Cervical Ganglion / Q000737:chemistry / Q000166:cytology* / Q000254:growth & development; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D015221:Potassium Channels; D016212:Transforming Growth Factor beta