Contribution of different calcium channels to long-term potentiation in superior cervical ganglion of the rat.
We explored the contribution of different calcium channel types to the long-term potentiation (LTP) of superior cervical ganglion of the rat. Right after a conditioning train of 40 Hz for 5 s, the maximum amplitude of the postsynaptic response (maximum potentiation) increased 5.6+/-0.5-fold. Potentiation decreased to 20% of its initial value within the following 70.0+/-8.0 min (LTP decay time). The contribution of P/Q-, N- and L-type calcium channels to LTP was studied by blocking their activity with synthetic funnel-web spider toxin (10 or 100 microM), omega-conotoxin GVIA (5 microM) or nifedipine (10 microM), respectively. The three blockers reduced the amplitude of the postsynaptic compound action potential before the conditioning train. After the train, all of the toxins reduced the LTP decay time and the integral of the amplitude versus time curve, defined as the LTP extent. In addition, all three blockers increased the maximum potentiation. Our results demonstrate that different calcium channel types contribute to ganglionic LTP. These effects may be by coupling excitation-secretion from different types of synaptic vesicles.
Cifuentes
F
F
Departamento de Biología Celular, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apartado Postal 70-228, Ciudad Universitaria, 04510 Mexico.
Licona
I I
II
De León
L
L
Medina
P
P
De-Miguel
F F
FF
Morales
M A
MA
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000145:classification / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation / Q000379:methods; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D051381:Rats; D017208:Rats, Wistar; D017783:Superior Cervical Ganglion / Q000166:cytology*; D009435:Synaptic Transmission / Q000187:drug effects; D013997:Time Factors
D002121:Calcium Channel Blockers; D015220:Calcium Channels