PMID- 18585443
OWN - NLM
STAT- MEDLINE
DCOM- 20081203
LR  - 20131121
IS  - 0306-4522 (Print)
IS  - 0306-4522 (Linking)
VI  - 155
IP  - 2
DP  - 2008 Aug 13
TI  - Nitric oxide modulates the firing rate of the rat supraoptic magnocellular 
      neurons.
PG  - 359-65
LID - 10.1016/j.neuroscience.2008.06.005 [doi]
AB  - In vitro, nitric oxide (NO) inhibits the firing rate of magnocellular 
      neurosecretory cells (MNCs) of hypothalamic supraoptic and paraventricular nuclei 
      and this effect has been attributed to GABAergic activation. However, little is 
      known about the direct effects of NO in MNCs. We used the patch-clamp technique 
      to verify the effect of L-arginine, a precursor for NO synthesis, and 
      N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of 
      NOS, on spontaneous electrical activity of MNCs after glutamatergic and GABAergic 
      blockade in Wistar rat brain slices. 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX) 
      (10 microM) and dl-2-amino-5-phosphonovaleric acid (dl-AP5) (30 microM) were used 
      to block postsynaptic glutamatergic currents, and picrotoxin (30 microM) and 
      saclofen (30 microM) to block ionotropic and metabotropic postsynaptic GABAergic 
      currents. Under these conditions, 500 microM L-arginine decreased the firing rate 
      from 3.7+/-0.6 Hz to 1.3+/-0.3 Hz. Conversely, 100 microM L-NAME increased the 
      firing rate from 3.0+/-0.3 Hz to 5.8+/-0.4 Hz. All points histogram analysis 
      showed changes in resting potential from -58.1+/-0.8 mV to -62.2+/-1.1 mV in the 
      presence of L-arginine and from -59.8+/-0.7 mV to -56.9+/-0.8 mV by L-NAME. 
      Despite the nitrergic modulator effect on firing rate, some MNCs had no 
      significant changes in their resting potential. In those neurons, hyperpolarizing 
      after-potential (HAP) amplitude increased from 12.4+/-1.2 mV to 16.8+/-0.7 mV by 
      L-arginine, but without significant changes by L-NAME treatment. To our 
      knowledge, this is the first demonstration that NO can inhibit MNCs independent 
      of GABAergic inputs. Further, our results point to HAP as a potential site for 
      nitrergic modulation.
FAU - Ventura, R R
AU  - Ventura RR
AD  - Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao 
      Paulo, Av. Bandeirantes, 3900, 14049-900 Ribeirao Preto, Sao Paulo, Brazil.
FAU - Aguiar, J F
AU  - Aguiar JF
FAU - Antunes-Rodrigues, J
AU  - Antunes-Rodrigues J
FAU - Varanda, W A
AU  - Varanda WA
LA  - eng
PT  - Journal Article
DEP - 20080608
PL  - United States
TA  - Neuroscience
JT  - Neuroscience
JID - 7605074
RN  - 31C4KY9ESH (Nitric Oxide)
RN  - 94ZLA3W45F (Arginine)
RN  - V55S2QJN2X (NG-Nitroarginine Methyl Ester)
SB  - IM
MH  - Action Potentials/drug effects/*physiology
MH  - Animals
MH  - Arginine/pharmacology
MH  - Female
MH  - Male
MH  - Membrane Potentials/drug effects/physiology
MH  - NG-Nitroarginine Methyl Ester/pharmacology
MH  - Neurons/drug effects/*physiology
MH  - Nitric Oxide/*physiology
MH  - Organ Culture Techniques
MH  - Patch-Clamp Techniques
MH  - Rats
MH  - Rats, Inbred WF
MH  - Supraoptic Nucleus/cytology/drug effects/*physiology
EDAT- 2008/07/01 09:00
MHDA- 2008/12/17 09:00
CRDT- 2008/07/01 09:00
PHST- 2008/04/14 00:00 [received]
PHST- 2008/06/02 00:00 [revised]
PHST- 2008/06/02 00:00 [accepted]
PHST- 2008/07/01 09:00 [pubmed]
PHST- 2008/12/17 09:00 [medline]
PHST- 2008/07/01 09:00 [entrez]
AID - S0306-4522(08)00880-4 [pii]
AID - 10.1016/j.neuroscience.2008.06.005 [doi]
PST - ppublish
SO  - Neuroscience. 2008 Aug 13;155(2):359-65. doi: 10.1016/j.neuroscience.2008.06.005. 
      Epub 2008 Jun 8.