# Myograph
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{{Short description|Device used to measure the force produced by a muscle}}
thumb|350px|A myograph recording from a pendulum myograph after an induced contraction. The upper line (m) represents the curve traced by the end of the myograph lever in connection with a muscle after stimulation of the muscle by a single induction-shock.
A '''myograph''' is any device used to measure the [force](/source/force) produced by a [muscle](/source/muscle) when under [contraction](/source/Muscle_contraction).[{{Cite book
| last1 = Blood
| first1 = Douglas C.
| first2 = Virginia P.
| last2 = Studdert
| title = Saunders Comprehensive Veterinary Dictionary
| publisher = Saunders Ltd.
| date = Jan 15, 1999
| url = https://archive.org/details/saunderscomprehe00doug
| isbn = 978-0-7020-2788-8
| url-access = registration
}}] Such a device is commonly used in [myography](/source/myography), the study of the velocity and intensity of muscular contraction.[{{Cite book
| last = Urdang
| first = Laurence
| title = -Ologies &- Isms: A Thematic Dictionary
| year = 1981
| publisher = Gale Research Co
| edition = 2
| isbn = 978-0-8103-1055-1}}]
A myograph can take several forms: for tubular structures such as [blood vessel](/source/blood_vessel)s these include the pressure myograph (where a segment of a blood vessel is cannulated at either or both ends) and the wire myograph (where the blood vessel segment is threaded onto a pair of pins or wires); for skeletal muscle other devices such as the [acceleromyograph](/source/acceleromyography) can be used.
In [pharmacology](/source/pharmacology), myography is used to record muscle contraction in [organ bath](/source/organ_bath) preparations. The related technique of [electromyography](/source/electromyography) (EMG) is used to measure the electrical activity of the muscle instead of force. In addition, there is an [optomyography](/source/optomyography) (OMG) technique that uses active near-infra-red optical sensors.
== Wire Myograph ==
A wire myograph is a type of laboratory apparatus that can measure the [contractility](/source/contractility) of luminal tissue segments smaller than 2 mm in diameter.[{{Citation |last1=Spiers |first1=Angela |title=A Guide to Wire Myography |date=2005 |url=https://doi.org/10.1385/1-59259-850-1:091 |work=Hypertension: Methods and Protocols |pages=91–104 |editor-last=Fennell |editor-first=Jérôme P. |access-date=2023-04-25 |place=Totowa, NJ |publisher=Humana Press |language=en |doi=10.1385/1-59259-850-1:091 |isbn=978-1-59259-850-2 |last2=Padmanabhan |first2=Neal |volume=108 |pmid=16028678 |editor2-last=Baker |editor2-first=Andrew H.|url-access=subscription }}][{{Citation |last=Olson |first=K. R. |title=DESIGN AND PHYSIOLOGY OF ARTERIES AND VEINS {{!}} Physiology of Capacitance Vessels |date=2011-01-01 |url=https://www.sciencedirect.com/science/article/pii/B978012374553800054X |encyclopedia=Encyclopedia of Fish Physiology |pages=1111–1118 |editor-last=Farrell |editor-first=Anthony P. |access-date=2023-04-25 |place=San Diego |publisher=Academic Press |language=en |isbn=978-0-08-092323-9}}] It is used by [pharmacologist](/source/pharmacologist)s to measure the effect of [test articles](/source/Test_article_(food_and_drugs)) on [blood pressure](/source/blood_pressure) or on airway contractility.[{{Cite web |title=The ultimate guide to wire myography [Protocol Included] |url=https://www.reprocell.com/blog/biopta/myograph |access-date=2023-04-25 |website=www.reprocell.com |language=en-us}}]
=== History of the wire myograph ===
Diagrams of the first ever wire myograph were revealed by Mulvany and Halpern in their 1976 paper "Contractile properties of small arterial resistance vessels in [...] rats".[{{Cite journal |last1=Mulvany |first1=M J |last2=Halpern |first2=W |date=July 1977 |title=Contractile properties of small arterial resistance vessels in spontaneously hypertensive and normotensive rats. |journal=Circulation Research |language=en |volume=41 |issue=1 |pages=19–26 |doi=10.1161/01.RES.41.1.19 |pmid=862138 |s2cid=1283485 |issn=0009-7330|doi-access=free }}] The group based the design of this apparatus on a technique developed by Bevan and Osher to measure arterial contractility ''[ex vivo](/source/ex_vivo)''.[{{Cite journal |last1=Bevan |first1=J. A. |last2=Osher |first2=J. V. |date=1972 |title=A direct method for recording tension changes in the wall of small blood vessels in vitro |journal=Agents and Actions |volume=2 |issue=5 |pages=257–260 |doi=10.1007/BF02087051 |issn=0065-4299 |pmid=4641160|s2cid=6905198 }}] Development of the wire myograph was significant because it allowed researchers to estimate the effect of novel drugs on blood pressure for the first time.