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Is diving reflex real, on terrestrial mammals?
Or the oxygen conserving effects of the dive response?
Some reflexes measured on dogs and rabbits nasal mucosa with cold water at 21 °C which are terrestrial mammals like us,
not marine, and give us an idea that they have these phenomena.
AND HERE ARE THE RESULTS:
1. Mechanical stimulation of the nasal mucous membrane caused a reduction or inhibition of respiration, bradycardia,
variable changes of arterial blood pressure, and a small rise in venous pressure.
2. Simultaneous measurements of arterial and venous pressures, and also of blood flow in various arteries by means of
an electromagnetic flowmeter indicate that the calculated vascular resistance increases in the intact limb, muscle, and
skin, and the vascular beds of the vertebral, superior mesenteric, renal and splenic arteries. No changes in vascular
resistance occur in the common carotid (neck major vessel that leads to brain) circulation.
3. Evidence is presented that the increase in vascular resistance is due to vasoconstriction, and occurs in the absence of
changes in pulmonary ventilation.
4. Stimulation of the nasal mucous membrane causes a reduction in volume of the spleen.
5. The respiratory and cardiovascular responses are reflex in nature, being abolished by the application of a local
anesthetic to the nose or by combined division of the maxillary and ethmoidal branches of the trigeminal nerves (V
cranial nerve that is a sensory nerve of the whole face). The cardiac response is mediated largely by the vagus nerves and
the vascular responses by sympathetic adrenergic fibers.
6. Cessation of the stimulus to the nose not infrequently results in the following temporary after-effects:
hyperventilation, tachycardia, hypertension, and vasodilatation in the intact limb and in muscle.
Or the oxygen conserving effects of the dive response?
Some reflexes measured on dogs and rabbits nasal mucosa with cold water at 21 °C which are terrestrial mammals like us,
not marine, and give us an idea that they have these phenomena.
AND HERE ARE THE RESULTS:
1. Mechanical stimulation of the nasal mucous membrane caused a reduction or inhibition of respiration, bradycardia,
variable changes of arterial blood pressure, and a small rise in venous pressure.
2. Simultaneous measurements of arterial and venous pressures, and also of blood flow in various arteries by means of
an electromagnetic flowmeter indicate that the calculated vascular resistance increases in the intact limb, muscle, and
skin, and the vascular beds of the vertebral, superior mesenteric, renal and splenic arteries. No changes in vascular
resistance occur in the common carotid (neck major vessel that leads to brain) circulation.
3. Evidence is presented that the increase in vascular resistance is due to vasoconstriction, and occurs in the absence of
changes in pulmonary ventilation.
4. Stimulation of the nasal mucous membrane causes a reduction in volume of the spleen.
5. The respiratory and cardiovascular responses are reflex in nature, being abolished by the application of a local
anesthetic to the nose or by combined division of the maxillary and ethmoidal branches of the trigeminal nerves (V
cranial nerve that is a sensory nerve of the whole face). The cardiac response is mediated largely by the vagus nerves and
the vascular responses by sympathetic adrenergic fibers.
6. Cessation of the stimulus to the nose not infrequently results in the following temporary after-effects:
hyperventilation, tachycardia, hypertension, and vasodilatation in the intact limb and in muscle.
