PMID- 8285292
OWN - NLM
STAT- MEDLINE
DCOM- 19940214
LR  - 20220309
IS  - 0002-9513 (Print)
IS  - 0002-9513 (Linking)
VI  - 265
IP  - 6 Pt 2
DP  - 1993 Dec
TI  - Steady-state osmotic modulation of cationic conductance in neurons of rat 
      supraoptic nucleus.
PG  - R1475-9
AB  - Whole cell patch-clamp recordings were obtained from isolated rat supraoptic 
      nucleus magnocellular neurosecretory cells (MNCs). Under current clamping, 
      hyperosmolality produced by the addition of 10-30 mM mannitol depolarized each of 
      25 cells tested. In contrast, reducing fluid osmolality from 295 to 265 
      mosmol/kgH2O had the reverse effect, hyperpolarizing 18 of 21 MNCs. Voltage-clamp 
      recordings in 43 cells revealed that the effects of hypo- and hyperosmolality, 
      respectively, were caused by decreases and increases in a nonselective cation 
      conductance reversing near -41 mV. Current-voltage analysis in Na(+)-free 
      solution revealed that the reversal potentials of currents elicited by increases 
      and decreases in osmolality both shifted to a value near -90 mV, suggesting that 
      a single ionic conductance is modulated by these stimuli. The relation between 
      cationic conductance and osmolality was specific, sensitive 
      (+2.14%.mosmol-1.kgH2O-1), and well-fit by linear regression (r = 0.96; n = 22 
      cells) between 275 and 325 mosmol/kgH2O. These results indicate that MNCs express 
      a depolarizing current that is active under steady-state conditions and that the 
      up- or downregulation of this current contributes to the excitation or inhibition 
      of these cells upon acute exposure to hypo- or hyperosmolar conditions.
FAU - Oliet, S H
AU  - Oliet SH
AD  - Centre for Research in Neuroscience, Montreal General Hospital, Quebec, Canada.
FAU - Bourque, C W
AU  - Bourque CW
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Am J Physiol
JT  - The American journal of physiology
JID - 0370511
RN  - 0 (Cations)
RN  - 3OWL53L36A (Mannitol)
SB  - IM
MH  - Animals
MH  - Cations/*metabolism
MH  - Electric Conductivity
MH  - Electrophysiology
MH  - *Homeostasis
MH  - Male
MH  - Mannitol/pharmacology
MH  - Neurons/*physiology
MH  - *Osmosis
MH  - Rats
MH  - Rats, Inbred Strains
MH  - Supraoptic Nucleus/*physiology
EDAT- 1993/12/01 00:00
MHDA- 1993/12/01 00:01
CRDT- 1993/12/01 00:00
PHST- 1993/12/01 00:00 [pubmed]
PHST- 1993/12/01 00:01 [medline]
PHST- 1993/12/01 00:00 [entrez]
AID - 10.1152/ajpregu.1993.265.6.R1475 [doi]
PST - ppublish
SO  - Am J Physiol. 1993 Dec;265(6 Pt 2):R1475-9. doi: 
      10.1152/ajpregu.1993.265.6.R1475.