Molecular mechanisms of odor sensing. VI. Some biochemical characteristics of a possible receptor for amino acids from the olfactory epithelium of the skate Dasyatis pastinaca and carp Cyprinus carpio

The 25 000 x g pellet of skate and carp olfactory tissue was found to contain structures with high affinity for amino acids (Kd approximately 10(-10) M). Results from competition experiments suggest that a multiplicity of types of olfactory binding sites exists in the skate and carp. Some parameters of a possible receptor for amino acids were evaluated. The isoelectric point of these sites solubilized with Triton X-100 was 5.35 and the molecular weight was about 120 000-150 000.

Transplants of olfactory mucosa in the anterior chamber of the eye: morphology, electrophysiology and biochemistry

The olfactory mucosa from neonatal rats was transplanted into the anterior chamber of the eye. By 6-8 weeks after transplantation, morphological analysis showed the presence of olfactory sensory neurons in the grafts. The summated receptor potentials evoked by n-amyl acetate and camphor had the peak amplitude of about three times less and the duration of response of about 8-10 times more than those from normal olfactory epithelium. 6 h after beta-[3H]-alanine administration into the anterior chamber, more than 70% of the radioactivity was present in the carnosine fraction. This indicates that carnosine synthetase is present in the grafts. The presented data suggest that the grafts contain mature olfactory sensory neurons.

Molecular mechanisms of olfactory reception. IV. Some biochemical characteristics of the camphor receptor from rat olfactory epithelium

Some parameters of the receptor element from the rat olfactory epithelium are evaluated; it is characterized by high affinity for camphor (KD = 1.5. x 10(-9) M). Triton X-100 has no marked effect on the binding of [3H]camphor. Neither RNAase nor phospholipase C affected [3H]camphor-binding activity. Pronase and trypsin abolished [3H]camphor binding activity by 65 and 40%, respectively. Sulfhydryl reagents decrease the binding of [3H]camphor by a factor of 5--8. The isoelectric point of the receptor solubilized with Triton X-100 is 4.8, as determined by isoelectric focusing. The molecular weight of the receptor as determined by gel electrophoresis is about 120 000. It is proposed that the camphor receptor is a membrane protein containing sulfhydryl groups and playing a key role in olfactory reception.

Molecular mechanisms of odor-sensing. II. Studies of fractions from olfactory tissue scrapings capable of sensitizing artificial lipid membranes to action of odorants

From the preparation obtained by ultrasonic disintegration of frog olfactory epithelium scraping, a fraction capable of sensitizing artificial phospholipid membranes to the action of some chemicals assumed to be odorants in frogs was isolated. In the presence of the active fraction, the membranes respond to the addition of camphor, linalool and musk ambrette by an increased permeability to Na+ and Ca2+. The main component of the active fraction is a nucleo-protein with molecular weight of no less than 100 000.

[Chromatographic fractionation of scraping components of frog olfactory tissues. Preparation of fractions capable of sensitizing artificial lipid membrane to odorants]

The fractionation of frog olfactory preparation by ion-exchange chromatography and gel filtration permitted to obtain fractions capable of making artificial lipid membranes sensitive to odorants, such as camphora, musc ambrette and linalool. The sensitizing agent present in active fractions is a high-molecular-weight (m.w. 100,000) protein containing substance. It is suggested that this agent is a component of a special transport system which may carry the odorous molecules to olfactory receptor cells or to remove them from olfactory tissues.