PMID- 22824541
OWN - NLM
STAT- MEDLINE
DCOM- 20130502
LR  - 20240325
IS  - 1873-6815 (Electronic)
IS  - 0531-5565 (Print)
IS  - 0531-5565 (Linking)
VI  - 47
IP  - 12
DP  - 2012 Dec
TI  - Effects of aging and levodopa on the laryngeal adductor reflex in rats.
PG  - 900-7
LID - S0531-5565(12)00198-2 [pii]
LID - 10.1016/j.exger.2012.07.008 [doi]
AB  - Dopaminergic neurotransmission plays an essential role in sensorimotor function, 
      and declines with age. Previously, we found the laryngeal adductor reflex (LAR) 
      was increased in excitation by a dopamine receptor antagonist. If this 
      airway-protective reflex is similarly affected by aging, it will interfere with 
      volitional control in older adults. The current study tested whether the LAR was 
      affected by aging, and whether such deficits were reversed by levodopa 
      administration in aging rats. We recorded thyroarytenoid (TA) muscle activity at 
      rest and during elicitation of LAR responses by stimulation of the internal 
      branch of the superior laryngeal nerve (iSLN) in 6-, 18- and 30-month-old rats 
      under alpha-chloralose anesthesia. Using paired stimuli at different 
      inter-stimulus intervals (ISIs), LAR central conditioning, resting muscle 
      activity, and reflex latency and amplitudes were quantified. Numbers of 
      dopaminergic neurons in the substantia nigra pars compacta (SNpc) were measured 
      using tyrosine hydroxylase staining. We found: (1) increased resting TA muscle 
      activity and LAR amplitude occurred with fewer dopaminergic neurons in the SNpc 
      in 18- and 30-month-old rats; (2) decreases in LAR latency and increases in 
      amplitude correlated with reduced numbers of dopaminergic neurons in the SNpc; 
      (3) test responses were greater at 1000ms ISI in 18-month-old rats compared with 
      6-month-old rats; and (4) levodopa administration further increased response 
      latency but did not alter muscle activity, response amplitude, or central 
      conditioning. In conclusion, increases in laryngeal muscle activity levels and 
      reflex amplitudes accompanied age reductions in dopaminergic neurons but were not 
      reversed with levodopa administration.
CI  - Copyright (c) 2012 Elsevier Inc. All rights reserved.
FAU - Feng, Xin
AU  - Feng X
AD  - Department of Otolaryngology, Wake Forest School of Medicine, Winston-Salem, NC 
      27157, United States. xfeng@wakehealth.edu
FAU - Xu, Zengrui
AU  - Xu Z
FAU - Butler, Susan G
AU  - Butler SG
FAU - Leng, Iris
AU  - Leng I
FAU - Zhang, Tan
AU  - Zhang T
FAU - Kritchevsky, Stephen B
AU  - Kritchevsky SB
LA  - eng
GR  - P30 AG021332/AG/NIA NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20120721
PL  - England
TA  - Exp Gerontol
JT  - Experimental gerontology
JID - 0047061
RN  - 0 (Dopamine Agents)
RN  - 46627O600J (Levodopa)
SB  - IM
MH  - Aging/pathology/*physiology
MH  - Animals
MH  - Dopamine Agents/*pharmacology
MH  - Dopaminergic Neurons/pathology
MH  - Laryngeal Muscles/drug effects/*physiology
MH  - Laryngeal Nerves/physiology
MH  - Levodopa/*pharmacology
MH  - Male
MH  - Rats
MH  - Rats, Inbred F344
MH  - Reaction Time/physiology
MH  - Reflex/drug effects/*physiology
PMC - PMC4819337
MID - NIHMS770547
EDAT- 2012/07/25 06:00
MHDA- 2013/05/03 06:00
PMCR- 2016/04/04
CRDT- 2012/07/25 06:00
PHST- 2012/04/23 00:00 [received]
PHST- 2012/07/12 00:00 [revised]
PHST- 2012/07/13 00:00 [accepted]
PHST- 2012/07/25 06:00 [entrez]
PHST- 2012/07/25 06:00 [pubmed]
PHST- 2013/05/03 06:00 [medline]
PHST- 2016/04/04 00:00 [pmc-release]
AID - S0531-5565(12)00198-2 [pii]
AID - 10.1016/j.exger.2012.07.008 [doi]
PST - ppublish
SO  - Exp Gerontol. 2012 Dec;47(12):900-7. doi: 10.1016/j.exger.2012.07.008. Epub 2012 
      Jul 21.