Molecular mechanisms of olfaction.
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Adenylyl Cyclases↗
Biomedical subjects
J Pevsner
Publications and source records attributed to J Pevsner.
Molecular cloning of odorant-binding protein: member of a ligand carrier family.
Odorant-binding protein (OBP) is found in nasal epithelium, and it selectively binds odorants. Three complementary DNAs encoding rat odorant-binding protein have now been cloned and sequenced. One clone contains an open reading frame predicted to encode an 18,091-dalton protein. RNA blot analysis confirms the localization of OBP messenger RNA in the nasal epithelium. This OBP has 33 percent amino acid identity to alpha 2-microglobulin, a secreted plasma protein. Other members of an alpha 2-microglobulin superfamily bind and transport hydrophobic ligands. Thus, OBP probably binds and carries odorants within the nasal epithelium to putative olfactory receptors.
Amino Acid Sequence↗
Odorant-binding protein and its mRNA are localized to lateral nasal gland implying a carrier function.
Odorant-binding protein selectively binds various odorants and is discretely concentrated in nasal mucosa and secretions. We have localized rat odorant-binding protein mRNA to the lateral nasal gland by in situ hybridization histochemistry and have also localized the protein to this gland by immunohistochemistry and by tritiated-odorant autoradiography. The lateral nasal gland extends a long duct toward the external nares. Odorant-binding protein, released from this duct, may transport odorants to olfactory receptor neurons.
Animals↗
Odorant-binding protein: localization to nasal glands and secretions.
An odorant-binding protein (OBP) was isolated from bovine olfactory and respiratory mucosa. We have produced polyclonal antisera to this protein and report its immunohistochemical localization to mucus-secreting glands of the olfactory and respiratory mucosa. Although OBP was originally isolated as a pyrazine binding protein, both rat and bovine OBP also bind the odorants [3H]methyldihydrojasmonate and 3,7-dimethyl-octan-1-ol as well as 2-isobutyl-3-[3H]methoxypyrazine. We detect substantial odorant-binding activity attributable to OBP in secreted rat nasal mucus and tears but not in saliva, suggesting a role for OBP in transporting or concentrating odorants.
Animals↗
Fetal methylazoxymethanol acetate-induced lesions cause reductions in dopamine receptor-mediated catalepsy and stereotypy.
Telencephalic hypoplasia induced by methylazoxymethanol acetate (MAM) resulted in increased activity of tyrosine hydroxylase in the striatum, indicative of a relative increase in the density of dopaminergic terminals in the remaining tissue. Administration of the dopamine receptor stimulant, apomorphine, or the receptor blocker, haloperidol, produced less stereotypy and catalepsy, respectively, in rats lesioned with methylazoxymethanol, compared to controls. These behavioral changes probably resulted from the loss of striatal perikarya and consequent decrease in nigrostriatal dopaminergic target sites caused by methylazoxymethanol.
Animals↗
Isolation and characterization of an olfactory receptor protein for odorant pyrazines.
The highly potent bell pepper odorant 2-isobutyl-3-[3H]methoxypyrazine [( 3H]IBMP) binds specifically and saturably to bovine and rat nasal epithelium. Specific binding is not detected in 11 other tissues assayed, and in the rat binding is 9 times higher in olfactory than in respiratory epithelium. We have purified to apparent homogeneity a soluble pyrazine odorant binding protein that constitutes approximately equal to 1% of the total soluble protein in bovine nasal epithelium. Polyacrylamide gel electrophoresis shows a single band of 19,000 Da and gel filtration data suggest that the native protein is a dimer of 38,000 Da. Binding of [3H]IBMP to the purified protein reveals two binding sites (Kd = 10 X 10(-9) M, Bmax = 135 pmol per mg of protein; Kd = 3 X 10(-6) M, Bmax = 25 nmol per mg of protein). The binding affinities of a homologous series of pyrazine odorants correlate with the human odor detection thresholds of these compounds. This correlation, together with the regional distribution of the protein, suggests that the protein is a physiologically relevant olfactory receptor.
Animals↗
Parametric influences on catalepsy.
Normal haloperidol-injected rats were tested on a standard catalepsy bar test, using varying bar heights, diameters, and descent latency measurement criteria. The results demonstrated that all these small procedural differences can markedly influence the duration of catalepsy exhibited by rats and should be standardized in catalepsy experiments.
Animals↗