PMID- 8413816
OWN - NLM
STAT- MEDLINE
DCOM- 19931117
LR  - 20180214
IS  - 0028-3835 (Print)
IS  - 0028-3835 (Linking)
VI  - 57
IP  - 5
DP  - 1993 May
TI  - Role of a T-type calcium current in supporting a depolarizing potential, damped 
      oscillations, and phasic firing in vasopressinergic guinea pig supraoptic 
      neurons.
PG  - 789-800
AB  - Guinea pig magnocellular neurosecretory cells (MNCs) of the supraoptic nucleus 
      (SON) were studied using the in vitro slice preparation. Intracellular recordings 
      were made with biocytin-filled electrodes, permitting immunocytochemical 
      identification of the recorded cells as arginine vasopressin- (AVP) versus 
      oxytocin- (OT) containing. Only AVP cells displaying a depolarizing potential 
      (DP) fired phasically. The DP was associated with a transient inward current 
      measured in voltage clamp, which exhibited a number of properties of the T-type 
      calcium current: activation threshold of -64 mV, time course of up to 250 ms, 
      blockade by nickel and augmentation by barium chloride. This current has not been 
      reported previously in SON neurons. The T-type current (IT) was always associated 
      with a damped oscillation of the membrane following the offset from 
      hyperpolarizing steps. In all cells tested, an apamin-sensitive 
      afterhyperpolarization (AHP) was observed, similar to the calcium-dependent 
      potassium current (IK, Ca) described in rat SON and other CNS regions. Therefore, 
      as with other CNS regions displaying damped oscillations, guinea pig SON cells 
      possess both an IT and an IK, Ca. We have previously described an Ih activating 
      at hyperpolarized potentials in these cells, which depolarizes the membrane to a 
      range in which the IT and IK, Ca can interactively support oscillations. In 
      summary, the IT and associated depolarizing potential appears to be a requisite 
      feature for phasic firing in AVP cells of guinea pig SON.
FAU - Erickson, K R
AU  - Erickson KR
AD  - Department of Physiology, Oregon Health Sciences University, Portland 97201.
FAU - Ronnekleiv, O K
AU  - Ronnekleiv OK
FAU - Kelly, M J
AU  - Kelly MJ
LA  - eng
GR  - DA 05158/DA/NIDA NIH HHS/United States
GR  - HD00718/HD/NICHD NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Switzerland
TA  - Neuroendocrinology
JT  - Neuroendocrinology
JID - 0035665
RN  - 113-79-1 (Arginine Vasopressin)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Arginine Vasopressin/*physiology
MH  - Calcium/*physiology
MH  - Electric Conductivity
MH  - Guinea Pigs
MH  - Immunohistochemistry
MH  - Neurons/physiology
MH  - Oscillometry
MH  - Supraoptic Nucleus/cytology/*physiology
EDAT- 1993/05/01 00:00
MHDA- 1993/05/01 00:01
CRDT- 1993/05/01 00:00
PHST- 1993/05/01 00:00 [pubmed]
PHST- 1993/05/01 00:01 [medline]
PHST- 1993/05/01 00:00 [entrez]
AID - 10.1159/000126438 [doi]
PST - ppublish
SO  - Neuroendocrinology. 1993 May;57(5):789-800. doi: 10.1159/000126438.