Respiration physiology
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Respiration physiology · Feb 1998
Skeletal muscle microcirculatory structure and hemodynamics in diabetes.
Within skeletal muscle, insulin-dependent (Type 1) diabetes produces straighter, narrower capillaries. To test the hypothesis that these microvascular alterations would be associated with impaired capillary hemodynamics, intravital microscopy techniques were used to study the in vivo spinotrapezius muscle microcirculation of age-matched control (C) and streptozotocin (STZ) induced diabetic (D) rats. D rats exhibited a marked reduction in body weight (C, 266 +/- 5 g; D, 150 +/- 6 g; P < 0.001). ⋯ This reduced calculated O2 delivery by 57% per unit tissue width and 41% per unit muscle mass. Capillary 'tube' hematocrit was unchanged from control values (C, 0.22 +/- 0.02; D, 0.22 +/- 0.02). We conclude that, in the diabetic state, microvascular remodeling is associated with a reduced proportion of 'flowing' capillaries and a reduction in RBC velocity and flux in these vessels such that skeletal muscle O2 delivery is markedly reduced.
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Respiration physiology · Feb 1998
Responses of laryngeal capsaicin-sensitive receptors to volatile anesthetics in anesthetized dogs.
The responses of laryngeal capsaicin (CAPS)-sensitive receptors to halothane, enflurane, isoflurane and sevoflurane were evaluated in anesthetized spontaneously breathing dogs from the afferent activity of the internal branch of the superior laryngeal nerve. The CAPS-sensitive receptors were clearly distinguished from irritant receptors by their responsiveness to CAPS and their lack of responsiveness to water. ⋯ In contrast, responses of irritant receptors to the volatile anesthetics were divided into three types (stimulation, inhibition or non-response), and did not differ among anesthetics. In conclusion, the present study demonstrated that the CAPS-sensitive receptors were consistently stimulated by halogenated volatile anesthetics and especially by halothane, enflurane, and isoflurane, and that these responses were dissimilar to the variable responses of irritant receptors.