PMID- 24068050
OWN - NLM
STAT- MEDLINE
DCOM- 20140123
LR  - 20211021
IS  - 1522-1490 (Electronic)
IS  - 0363-6119 (Print)
IS  - 0363-6119 (Linking)
VI  - 305
IP  - 10
DP  - 2013 Nov 15
TI  - Protection of signal processing at low temperature in baroreceptive neurons in 
      the nucleus tractus solitarius of Syrian hamsters, a hibernating species.
PG  - R1153-62
LID - 10.1152/ajpregu.00165.2013 [doi]
AB  - We previously described synaptic currents between baroreceptor fibers and 
      second-order neurons in the nucleus tractus solitarius (NTS) that were larger in 
      Syrian hamsters than in rats. This suggested that although electrical activity 
      throughout the hamster brain decreased as brain temperature declined, the greater 
      synaptic input to its NTS would support continued operation of cardiorespiratory 
      reflexes at low body temperatures. Here, we focused on properties that would 
      protect these neurons against potential damage from the larger synaptic inputs, 
      testing the hypotheses that hamster NTS neurons exhibit: 1) intrinsic 
      N-methyl-D-aspartate receptor (NMDAR) properties that limit Ca(2+) influx to a 
      greater degree than do rat NTS neurons and 2) properties that reduce gating 
      signals to NMDARs to a greater degree than in rat NTS neurons. Whole cell 
      patch-clamp recordings on anatomically identified second-order NTS baroreceptive 
      neurons showed that NMDAR-mediated synaptic currents between sensory fibers and 
      second-order NTS neurons were larger in hamsters than in rats at 33 degrees C and 15 degrees C, 
      with no difference in their permeability to Ca(2+). However, at 15 degrees C, but not at 
      33 degrees C, non-NMDAR currents evoked by glutamate released from baroreceptor fibers 
      had significantly shorter durations in hamsters than in rats. Thus, hamster 
      NMDARs did not exhibit lower Ca(2+) influx than did rats (negating hypothesis 1), 
      but they did exhibit significant differences in non-NMDAR neuronal properties at 
      low temperature (consistent with hypothesis 2). The latter (shorter duration of 
      non-NMDAR currents) would likely limit NMDAR coincidence gating and may help 
      protect hamster NTS neurons, enabling them to contribute to signal processing at 
      low body temperatures.
FAU - Sekizawa, Shin-Ichi
AU  - Sekizawa S
AD  - Department of Pharmacology, University of California, Davis, California;
FAU - Horwitz, Barbara A
AU  - Horwitz BA
FAU - Horowitz, John M
AU  - Horowitz JM
FAU - Chen, Chao-Yin
AU  - Chen CY
LA  - eng
GR  - R01 HL-091763/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20130925
PL  - United States
TA  - Am J Physiol Regul Integr Comp Physiol
JT  - American journal of physiology. Regulatory, integrative and comparative 
      physiology
JID - 100901230
RN  - 0 (Receptors, N-Methyl-D-Aspartate)
SB  - IM
MH  - Animals
MH  - Body Temperature Regulation/physiology
MH  - *Cold Temperature
MH  - Cricetinae
MH  - Gene Expression Regulation/physiology
MH  - Hibernation/*physiology
MH  - Male
MH  - Membrane Potentials/physiology
MH  - Neurons/cytology/physiology
MH  - Pressoreceptors/*physiology
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Receptors, N-Methyl-D-Aspartate/genetics/metabolism
MH  - Signal Transduction/*physiology
MH  - Solitary Nucleus/cytology/*physiology
PMC - PMC3841799
OTO - NOTNLM
OT  - AMPAR
OT  - NMDAR
OT  - baroreflex
OT  - cold
EDAT- 2013/09/27 06:00
MHDA- 2014/01/24 06:00
PMCR- 2014/11/15
CRDT- 2013/09/27 06:00
PHST- 2013/09/27 06:00 [entrez]
PHST- 2013/09/27 06:00 [pubmed]
PHST- 2014/01/24 06:00 [medline]
PHST- 2014/11/15 00:00 [pmc-release]
AID - ajpregu.00165.2013 [pii]
AID - R-00165-2013 [pii]
AID - 10.1152/ajpregu.00165.2013 [doi]
PST - ppublish
SO  - Am J Physiol Regul Integr Comp Physiol. 2013 Nov 15;305(10):R1153-62. doi: 
      10.1152/ajpregu.00165.2013. Epub 2013 Sep 25.