American journal of physiology. Heart and circulatory physiology
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Am. J. Physiol. Heart Circ. Physiol. · Jul 2001
Endothelin-1 and nitric oxide synthase in short rebound reaction to short exposure to inhaled nitric oxide.
On withdrawal of inhalation of nitric oxide (INO) administered after lung injury, pulmonary artery pressure (PAP) and arterial oxygen tension (Pa(O(2))) may deteriorate more than before INO (rebound response). In this study, we investigated the possible roles of endothelin (ET)-1 and nitric oxide (NO) synthase (NOS) activity in the short rebound reaction to short-term inhalation of NO. Twenty-six anesthetized mechanically ventilated piglets were given endotoxin infusion. ⋯ Lung tissue expression and plasma concentration of ET-1 increased during INO, and plasma ET-1 increased further after its withdrawal. Activity of constitutive NOS decreased during INO, whereas that of inducible NOS was unchanged. Upregulation of ET-1 and downregulation of NOS activity may have influenced the short rebound reaction to short-term INO.
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Am. J. Physiol. Heart Circ. Physiol. · Jul 2001
Expression of metabotropic glutamate receptors in nodose ganglia and the nucleus of the solitary tract.
The purpose of this study was to identify the complement of metabotropic glutamate receptors (mGluRs) expressed in nodose ganglia and the nucleus tractus solitarius (NTS). mRNA from these tissues was isolated and amplified with standard RT-PCR with primers specific for each mGluR subtype. The results of this analysis showed that the NTS expresses all eight mGluR subtypes, whereas nodose ganglia express only group III mGluRs: mGluR4, mGluR6, mGluR7, and mGluR8. Application of the group III-specific mGluR agonist L-(+)-2-amino-4-phosphonobutyric acid (100 microM) reversibly inhibited voltage-gated calcium currents isolated from DiI-labeled aortic baroreceptor neurons and unlabeled nodose neurons. The results of this study suggest that group III mGluRs are the primary mGluR subtype expressed in visceral afferent neurons and that these receptors may be involved in afferent central transmission.