MARINE TOXINS AND VENOMOUS AND POISONOUS MARINE ANIMALS
351
occurred at the site of the injury. He suggested that the venom
contained hyaluronidase.
Russell and Emery (1960) analyzed extracts from the venomcontaining tissues of T. vipera and T. drrrco. The freshly prepared
extracts had a fishy taste and ammoniacal odor ; pH was 6.78. The
results of the determinations are shown in Table VIII. Assays of the
dialyzed and non-dialyzable solutions indicated that the lethal portion
was non-dialyzable.
The extracts had no deleterious effect on mammalian neuromuscular transmission. When large amounts of the extract were added
t o the nerve-muscle bath, there was some shortening of the muscle and
a very gradual depression of both the directly and indirectly elicited
contractions, but at no time was there any evidence of a differential
that could be attributed to changes a t the neuromuscular junction.
I n cats the venom produced a precipitous fall in systemic arterial
pressure concomitant with changes in the pulse pressure, cardiac rate,
pulmonary arterial pressure, venous and cisternal pressures, respiration,
and the electrocardiogram and electroencephalogram (Fig. 19). The
findings are similar to those produced by stingray venom and certain
of the venoms of other fishes.
The electrocardiograms demonstrate that the venom can produce
both changes in rhythm and injury to the heart muscle. The fall in
pulmonary artery pressure indicates either a failure of the heart to
maintain an effective stroke volume, or a decrease in pulmonary
resistance. The latter seems unlikely ; studies of pulmonary artery
blood flow using a gated sine-wave electromagnetic flowmeter indicate
that the blood flow in this vessel is reduced during the period of
decreased pressure. The findings of lowered pulmonary arterial pressure
and flow, a decrease in heart rate with various degrees of auriculoventricular block, and evidence of heart muscle injury may be interpreted to mean that some degree of cardiac failure is probably responsible for the fall in systemic arterial pressure and the rise in
venous and cisternal pressures. Smaller amounts of weeverfish venom
produced transient vasoconstriction or vasodilatation, depending on
the quantity injected. With these doses there is little or no deleterious
effect upon the heart, although there may be some changes in cardiac
rate and in respiratory rate.
The depression in central nervous system activity seen following
the intravenous injection of a lethal dose of the toxin (Fig. 19), can
be attributed to ischemic anemia produced by the lowered systemic
arterial pressure. The wave pattern is typical of that which occurs
during cardiovascular failure from any of a number of causes. However,
351
occurred at the site of the injury. He suggested that the venom
contained hyaluronidase.
Russell and Emery (1960) analyzed extracts from the venomcontaining tissues of T. vipera and T. drrrco. The freshly prepared
extracts had a fishy taste and ammoniacal odor ; pH was 6.78. The
results of the determinations are shown in Table VIII. Assays of the
dialyzed and non-dialyzable solutions indicated that the lethal portion
was non-dialyzable.
The extracts had no deleterious effect on mammalian neuromuscular transmission. When large amounts of the extract were added
t o the nerve-muscle bath, there was some shortening of the muscle and
a very gradual depression of both the directly and indirectly elicited
contractions, but at no time was there any evidence of a differential
that could be attributed to changes a t the neuromuscular junction.
I n cats the venom produced a precipitous fall in systemic arterial
pressure concomitant with changes in the pulse pressure, cardiac rate,
pulmonary arterial pressure, venous and cisternal pressures, respiration,
and the electrocardiogram and electroencephalogram (Fig. 19). The
findings are similar to those produced by stingray venom and certain
of the venoms of other fishes.
The electrocardiograms demonstrate that the venom can produce
both changes in rhythm and injury to the heart muscle. The fall in
pulmonary artery pressure indicates either a failure of the heart to
maintain an effective stroke volume, or a decrease in pulmonary
resistance. The latter seems unlikely ; studies of pulmonary artery
blood flow using a gated sine-wave electromagnetic flowmeter indicate
that the blood flow in this vessel is reduced during the period of
decreased pressure. The findings of lowered pulmonary arterial pressure
and flow, a decrease in heart rate with various degrees of auriculoventricular block, and evidence of heart muscle injury may be interpreted to mean that some degree of cardiac failure is probably responsible for the fall in systemic arterial pressure and the rise in
venous and cisternal pressures. Smaller amounts of weeverfish venom
produced transient vasoconstriction or vasodilatation, depending on
the quantity injected. With these doses there is little or no deleterious
effect upon the heart, although there may be some changes in cardiac
rate and in respiratory rate.
The depression in central nervous system activity seen following
the intravenous injection of a lethal dose of the toxin (Fig. 19), can
be attributed to ischemic anemia produced by the lowered systemic
arterial pressure. The wave pattern is typical of that which occurs
during cardiovascular failure from any of a number of causes. However,