Effects of Different Ion Concentrations on the Contraction of the Striated Muscles of the Frog Estareja, Engemar C.
Biology Student, Department of Biology, College of Science Polytechnic University of the Philippines Abstract
Muscle is one of the most important organ in the body that accounts for the most essential function in the maintenance of movement in a biological organism. These muscles have different properties, suitable to produce movement and enables tension made by contraction and relaxation by which specific ion interactions play a crucial role in making such movements possible. This study aims to determine the effect of different ions on muscle contraction and observe the structural changes on the striated muscles upon subjection to the different ion solutions. Muscle strips was obtained from the striated muscle of the frog and each slide containing the strips were bathed in the different solutions, slide A was NaCl, slide B was KCl, in slide C was CaCl2 and slide D (control) was Ringer ’s solution. The length of the muscle strips were measured before and after adding the follow-up solutions for the computation of percent of contraction. In muscle response to salt solutions, one hind leg and heart of the frog were removed and placed on a separate petri dish containing saturated KCl solution. Heart soaked in saturated solution of Calcium chloride has the longest contraction time same applies to hind legs that were soaked in Calcium chloride solution. After conducting the activity it can be concluded that different ions or particular ions such as potassium, sodium and calcium has a specific interaction within the skeletal and cardiac muscle contraction and relaxation phase. Keywords: muscle contraction, ions, striated muscle
Introduction
Muscular
movement
of
contraction
and
varies
being
involuntary
and
voluntary
relaxation is one of the most complex and crucial
respectively (Berne and Levy, 1993). As a
physiological system in an organism. Muscles
process, calcium ions that are stored in the
possesses
to
sarcoplasmic reticulum are released following
produce movement and enables tension made
opening of ion channels upon receiving stimulus,
by contraction (Hopkins, 2006). These properties
and binds to tropomyosin-troponin complex,
however must be integrated with accompanying
exposing the actin filaments. An ATP molecule
several processes for one contraction event to
will bind to the myosin head, and will be
occur.
muscle
converted to ADP and Pi. The myosin then
contraction rhythm is different from the
connects to the actin forming cross bridges and
contraction of the skeletal muscles, as these two
the conversion of ATP to ADP and Pi will
different
properties
Physiologically,
suitable
cardiac
generate a sliding movement towards the center
whenever
a
of the sarcomere. When a new ATP binds to the
(Harvey,2008).
single
cell
is
stimulated
myosin head, the cross bridges break and the myosin head is unattached to actin and return to
These muscle contraction is greatly
its relaxed position (Clark et. al., 2002). The
affected by different ions which play an
myocardium, like skeletal muscle, responds to
important role in muscular physiology, from the
stimulation by depolarization of the membrane,
start of transmission of the impulse, up to the
which
the
attachment of actin molecules to myosin as it is
contractile proteins and ends with relaxation
exposed through binding of calcium ions to
and return to the resting state. However, unlike
troponin (Hopkins, 2005: Brien et. al., 1993). This
skeletal
graded
study aims to determine the effect of different
contractions depending on the number of
ions on muscle contraction and observe the
muscle cells that are stimulated, the cardiac
structural changes on the striated muscles upon
muscle cells are interconnected in groups that
subjection to the different ion solutions.
is
followed
muscle,
by
shortening
which
shows
of
respond to stimuli as a unit, contracting toge ther METHODOLOGY
A. Ions and Muscle Contraction Very thin strips of ventricular muscle were cut parallel to the direction of the muscle fibers using scalpel and forceps. The strips were less than 1 mm in width and anywhere in 2030mm in length. Thin muscle strips were transferred and oriented onto each slide with the use of forceps and 5 drops o f Ringer’s solution was added to cover the strips. Excess solution was drained by tilting the slide and wiping it with a tissue paper. The muscle length was measured before and after subjection to the solution and the percent contraction was calculated using the formula given below. The solutions are: NaCl solution for slide A, KCl for slide B, 1:1 solution of 1 mM Cacl2 to slide C and Ringer’s solution for slide D as for the control .
The Following equation was used to determine the percent of contraction:
B. Muscle Response to Salt solutions Ringer’s solution was used to wash the blood
from the removed hind legs and heart of the frog. The hind leg and heart was placed separately on a petri dish containing saturated CaCl2 and KCL solution. The response of the heart and hind leg was observed and noted on how long the muscle responded. RESULTS AND DISCUSSION A. Ions and Muscle Contraction Ringer’s solution was used as the constant
solution before the application of the following;
data presented, it exhibited that the action
NaCl in slide A, KCl in slide B, CaCl2 in slide C, and
might due to personal error.
water in slide D. According to the study of Curtis in 1962, that both fall in membrane potential and resistance can be explained by assuming
45
that
40 35 30
Ringer’s
solutions
increased
the
permeability of the membrane to all ions and normal range of resting membrane potential. A thin muscle strip observed under the microscope showed muscle fibers at its resting potential.
25 20 15 10 5
Length
Length
after
before
exposure (in
exposure (in
mm)
0
mm ) A (NaCl)
20.00 ± 0.70
14.33±1.02
B (KCl)
22.33 ± 1.08
18.67±0.88
C (CaCl 2)
23.00±1.41
19.00±1.15
D (control)
24.67±1.08
23.33±1.20
E(saturated
21.00±0.71
18.33±0.33
Figure 1. Shows the mean percentage contraction of each
muscle fiber when subjected to the different solutions.
KCl)
B. Muscle response to salt solution
Table 1. Percentage Contraction of Muscle in the Varying
Solutions
Muscle
Time
Type
The muscle strip under NaCl solution was curled and the length was decreased significantly due to the sudden sodium influx. The difference in electric membrane potential inside and outside the membrane will cause the ions t o move. Followed by calcium, calcium generally aids in contraction by reacting with regulatory proteins that in the absence of calcium prevent interaction of actin and myosin (Szent - Gyorgi, 1975).
KCl
also
induced
contraction
but
theoretically. KCl should help in the relaxation state of the muscles since there would be an efflux of potassium. As prior to the control, it should have no muscle contraction but in the
Heart Hind Leg
CaCl2
KCl
20 mins and
1 min and 40
13 secs
secs
7 mins and
5 mins and 25
4 secs
secs
Table 2. Response of Heart and Hind Legs in KCl and CaCl2
The heart representing a cardiac muscle and the hind leg for a skeletal muscle were subjected in two (2) different kinds of salt solution, but before
subjecting the heart of the frog in kind of salt solution. Ringer’s solution which contains equal
amounts of salt and other substance to make the solution neutral, was used to neutralize the
charge or the resting membrane potential of
contraction of the striated muscles. Calcium
cells in the muscles used in this activity (De mello,
allows excitation-contraction coupling system.
1973).
Chlorine is responsible for repolarization of the membrane. KCl is responsible for potentiation.
Heart subjected to saturated Calcium Chloride
Water containing hydrogen and oxygen allows
has the slowest contraction time (20 mins and
the proteins that were present in the contractile
13 seconds) while heart subjected to saturated
apparatus to move easily allowing contractions
Potassium Chloride solution lasted for 1 minute
to generate. The contractions of muscle are
and 40 seconds. Potassium is specifically needed
higher on the ions that trigger action potential to
for voltage-gated potassium channels to work in
create contractions and lower on the ions that
the outer membranes of cardiac muscle cells
triggers resting membrane potential to create
(Parikh and Webb, 2012). These channels open
relaxation. Differences in the ion concentrations
in response to a change in voltage and are
inside and outside the membrane create a
responsible for terminating action potentials and
significant effect on the reaction of the striated
contractions
muscles.
while
initiating
repolarization.
Likewise potassium ions are an important element in all phases of heart generating action
The observation of the hind legs must be done
potential. In heart contraction, during phase 0,
immediately to see the contractions in the salt
heart cells become less permeable to potassium
solutions.
and voltage-gated sodium channels open, producing rapid depolarization and contraction.
Literature Cited
During phase 2, there is an increased membrane permeability to calcium, which e ventually allows
ADRIAN, R. H. 1956. The effect of internal and
more sodium to flow into the heart cells by
external potassium concentration on the
which during phase 3, sodium and calcium
membrane potential of frog muscle. J.
channels close, which leads to heart muscle
Physiol. (London). 133:631.
relaxation. (Pinell et al., 2007). In hind legs same principle can be applicable, potassium is important ion in generating action potential thus
Bennetts B, Rychkov GY, Ng HL, Morton CJ,
saturated potassium chloride enable the hind
Stapleton D, Parker MW, Cromer BA.
legs to contract and last its contraction time (5
2005.Cytoplasmic ATP-sensing domains
minutes and 25 seconds)
regulate gating of skeletal muscle ClC-1 chloride channels. J Biol Chem 280:
Moreover during skeletal muscle contraction,
32452– 32458.
there is a phase called plateau phase which is achieved by a balance between the influx of
BOYLE, P. J., and E. J. CONWAY. 1941. Potassium
Ca++ through Ca++ channels and the efflux of
accumulation in muscle and associated
several types K+ channels.
changes. J. Physiol. (London) 100:1.
CONCLUSION
Carolina Biological Supply Company . 2006. Contraction of Glycerinated Muscle
Ions greatly affect the mechanism of the
with ATP Instruction Manual. USA.
sjgp.rupress.org. Chandler, Stephanie. 2011. What Role Does Potassium Play in Muscle Contraction?
Pinnell, J., S. Turner and S. Howell, Cardiac
http://www.livestrong.com/article/49
muscle
3009 -what-role-does-potassium-play-
Anaesth Crit Care Pain (2007) 7 (3): 85-
in muscle-contraction/#ixzz2aJGI2oTB
88.doi: 10.1093/bjaceaccp/mkm013
Curtis, B.A. 1962. Some Effects of Ca-Free Choline-Ringer Solution on Frog Skeletal Muscle. J. Physiol., 166.pp.75-86. De Mello, W.C., Membrane Sealing in Frog Skeletal- Muscular Fibers, Proc. Nat. Acad. Science, Volume 70 No. 4, Pp 982984, 1973 Hodgkin AL, Horowicz P. 1959. The influence of potassium and chloride ions on the membrane potential of single muscle fibres.J Physiol. October; 148(1): 127 – 160.
Hopkins, Philip M. 2006. Skeletal muscle physiology. Board of Management and Trustees of the British Journal of Anaesthesia. Continuing Education in Anaesthesia, Critical Care & Pain | Volume6Number1.doi10.1093/bjaceacc p/mki062http://ceaccp.oxfordjournals. or g/. Regulation of Skeletal Muscle Contraction: Ashley, C.C., and Ridgway, E.B. (1968). Aspects of the relationship between membrane potential, calcium transient and tension in single barnacle muscle fibers. J. Physiol. 200, 74-76P. MIYAMOTO, M. and J. I. HUBBARD. 1972. On the Inhibition of Muscle Contraction Caused by Exposure to Hypertonic Solution.
Physiology,
Contin
Educ
A G Szent-Györgyi.1975. Calcium regulation of muscle contraction. Biophys J.
