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Related post: consist in stimulation, with subsequent paralysis, being similar to the
effects of asphyxia.
Salt Action on Phagocytosis. The sensitiveness of cells to small changes in osmotic
concentration is shown by the phagocytic power of leucocytes. According to H. Ham-
burger and his pupils, 1908 and 1910, the phagocytic power is decreased by very small
changes of the osmotic concentration of the serum, such as may occur under physiologic
conditions. All anisotonic solutions are injurious, but especially increased concentra-
tions. The leucocytes recover when the normal concentration is Buy Promethazine Online restored. NaCl
causes but little Purchase Promethazine Online injury apart from the Generic Promethazine osmotic effect. Nal is more toxic than NaBr. Of
other ions, a slight excess of calcium stimulated, while decreased activity resulted from
a larger excess, and from reduction of calcium as by fluorids or citrates. Ba and Sr do
not Buy Promethazine have the stimulant action, so that it is not due to valence. Diminution of the
normal alkalinity was deleterious, and to a less Cheap Promethazine degree also an excessive alkalinity.
Osmotic Response of Muscle. Striped muscle is semipermeable, smooth muscle is
permeable. This different permeability is reflected in their response. Immersion in
water, /./., causes striped muscle to become rigid and to shorten, smooth muscle to
lengthen. The effects are counteracted by 2 per cent. NaCl (Meigs, 1912). Dale,
1913, also found the tone of smooth muscle increased by hypo- and diminished by hyper-
tonic Ringer's solutions. Slightly hypertonic solutions increased the response to in-
hibitory drugs and decreased the effects of stimulant drugs. Slightly hypotonic solu-
tions had the opposite effect. The muscle of the Venus agrees with non-striated
muscle, in being permeable (Meigs, 1914).
Faligue increases the molecular concentration (depression of freezing point) of
excised skeletal muscle by 36 per cent, by the breaking down of molecules. This does
638 MANUAL OF PHARMACOLOGY
not occur when the circulation is intact, for the differences are then equalized by ex-
change with th-j blood (A. R. Moore, 1916).
Ion Effects on Muscle. The immersion of muscle in various solutions
produces marked effects even when osmotic changes are excluded by
having the solutions isotonic. These must therefore be referred to ion
The muscles lengthen or shorten; the excitability may be diminished
or increased; spontaneous rhythmic contractions may appear ; or the mus-
cle may develop "contact irritability" so that it will react to stimuli
which are ordinarily ineffective. Invertebrate and mammalian muscles,
exhibit similar phenomena if proper conditions are maintained.
ACTIONS OF ELECTROLYTES
Importance of Electrolytes. Muscles soon lose their excitability com-
pletely in solutions of non-electrolytes; but this returns when they are
replaced in saline solutions. A medium containing electrolytes is there-
fore essential to muscular contraction; indeed, any change in the ions Promethazine Online pro-
duces alterations in the muscular functions. The different ions are not
equally effective. It appears that the nature of the cathions is more
important than the anions. The ions arrange themselves in the usual
lyotropic series, the Na and I end being the most favorable, and the K
and citrate end being the most unfavorable.
Toxic Action of Single Salts. Immersion in any solution of a single salt also renders
muscle inexcitable, but with very different rapidity. These differences follow the lyo-
tropic series in the same sense.
Rhythmic Contractions of Skeletal Muscle. These generally develop before the
irritability is lost, when muscle is immersed in solutions of a single electrolyte (Loeb,
1899). If a certain proportion of a calcium salt is added, the rhythmic property dis-
appears again. The rhythmic contraction of the cardiac muscle or of medusae also dis-
appears when calcium is added. Rhythmic contractibility is not therefore a property
characteristic of cardiac muscle, but is inherent in all muscular tissues. The reason
why the contraction of the heart is ordinarily rhythmic, and that of skeletal muscle not,
lies in the fact that the ions in the heart are balanced so as to favor rhythmic contrac-
tions, Order Promethazine and in the skeletal muscle they are not so balanced.
Ciliary and Muscular Movement. R. S. Lillie (1902) has studied the effects of ions
on the larvae of a sea- worm (Arenicola), which executes both ciliary and muscular
movements. He found that the presence of magnesium in the mixture favors the con-
traction of the cilia, calcium of the muscles; potassium hinders both. Parker (1905)
has found that potassium reverses the stroke of certain cilia.
Ion Actions on Heart. These are highly important to the cardiac Buy Cheap Promethazine
contractions. The excised hearts of cold-blooded animals soon stop their
beat when immersed in solutions of non-electrolytes (Carlson); but they
continue to contract rhythmically for a long time in certain salt solutions.
Analogous phenomena are observed in the perfusion of mammalian hearts.
The solutions must contain Na, K, and Ca ions; and these must be in a
fairly definite "balanced" ratio, as in Ringer's or Locke's solutions or
their modifications. Deficiency or excess Purchase Promethazine of these ions cause derange-
ment of function and are equally fatal. The ratio is much more impor-
tant than the absolute quantity of the ions. The anions are relatively
R61e of the Individual Cathions. NaCl is indispensable to the rhythmic contractions
of the heart; but when present alone it produces relaxation and is finally fatal to the
heart as to other tissues. The addition of K ions produces a diastolic tendency and
standstill. Ca and NaCl produce increased systolic contractions but the diastoles
ACTIONS OF ELECTROLYTES 639
become imperfect and deficient. Starting with a balanced Ringer's solution, sudden
increase of K results in slowing and weakening (often halving of the rate), and decreased
excitability to vagus stimulation, and with higher concentrations in arrest. This may
be removed by the injection of Ca, or by accelerator stimulation. Increase of Ca acts
like accelerator stimulation, resulting in increased excursions, prolongation and fusion
of systoles, and systolic standstill. Ca is also necessary for the inhibitory response to
vagus stimulation; but excessive Ca concentration paralyzes the vagus (Schiff ; Cazzola,
1913; Boehm, 1914). The K or Ca actions predominate when the percentage of one
predominates about three and one-half times over the other. The effects of K-free
Ringer's solution resemble Ca predominance. Ca-free Ringer's solution increases the
rate i.e., the result is the opposite of K in the presence of Ca. Deficiency of Ca, K
or OH ions shortens the survival of the heart (Boehm, 1914).
Theories of Cardiac Ion Relations. In the light of these data attempts have been
made to assign definite functions to the individual ions. They are not very satisfac-
tory, except in that they emphasize that Ca and K have opposite and complementary
effects (Ringer, 1882), Ca for promoting contraction and K relaxation. Loeb, 1899,
attributed the contractions to the Na ions, but requiring the presence of Ca. Howell, Order Promethazine Online
1898 and 1906, believes that Ca is concerned in the contraction and K and Na in the
relaxation; that these ions enter alternately into relation with the contractile substance;
that accelerator stimulation liberates Ca and vagus stimulation K ions. Martin, 1913,
assumes with Howell that Ca promotes the conversion of stable into unstable energy-
yielding material; that Na brings about the actual dissociation and thus initiates the
beat (Lingle); and that K antagonizes both the Na and Ca. The chemic conditions
of cardiac activity are reviewed by Tigerstedt, Erg. Physiol., 12: 269.
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