On the terminology for describing the length-force relationship and its changes in airway smooth muscle.
The observation that the length-force relationship in airway smooth muscle can be shifted along the length axis by accommodating the muscle at different lengths has stimulated great interest. In light of the recent understanding of the dynamic nature of length-force relationship, many of our concepts regarding smooth muscle mechanical properties, including the notion that the muscle possesses a unique optimal length that correlates to maximal force generation, are likely to be incorrect. To facilitate accurate and efficient communication among scientists interested in the function of airway smooth muscle, a revised and collectively accepted nomenclature describing the adaptive and dynamic nature of the length-force relationship will be invaluable. Setting aside the issue of underlying mechanism, the purpose of this article is to define terminology that will aid investigators in describing observed phenomena. In particular, we recommend that the term "optimal length" (or any other term implying a unique length that correlates with maximal force generation) for airway smooth muscle be avoided. Instead, the in situ length or an arbitrary but clearly defined reference length should be used. We propose the usage of "length adaptation" to describe the phenomenon whereby the length-force curve of a muscle shifts along the length axis due to accommodation of the muscle at different lengths. We also discuss frequently used terms that do not have commonly accepted definitions that should be used cautiously.
Bai
Tony R
TR
James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia, Vancouver, Canada.
Bates
Jason H T
JH
Brusasco
Vito
V
Camoretti-Mercado
Blanca
B
Chitano
Pasquale
P
Deng
Lin Hong
LH
Dowell
Maria
M
Fabry
Ben
B
Ford
Lincoln E
LE
Fredberg
Jeffrey J
JJ
Gerthoffer
William T
WT
Gilbert
Susan H
SH
Gunst
Susan J
SJ
Hai
Chi-Ming
CM
Halayko
Andrew J
AJ
Hirst
Stuart J
SJ
James
Alan L
AL
Janssen
Luke J
LJ
Jones
Keith A
KA
King
Greg G
GG
Lakser
Oren J
OJ
Lambert
Rodney K
RK
Lauzon
Anne-Marie
AM
Lutchen
Kenneth R
KR
Maksym
Geoffrey N
GN
Meiss
Richard A
RA
Mijailovich
Srboljub M
SM
Mitchell
Howard W
HW
Mitchell
Richard W
RW
Mitzner
Wayne
W
Murphy
Thomas M
TM
Paré
Peter D
PD
Schellenberg
R Robert
RR
Seow
Chun Y
CY
Sieck
Gary C
GC
Smith
Paul G
PG
Smolensky
Alex V
AV
Solway
Julian
J
Stephens
Newman L
NL
Stewart
Alastair G
AG
Tang
Dale D
DD
Wang
Lu
L
D000818:Animals; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology*; D009626:Terminology as Topic; D014132:Trachea / Q000502:physiology*