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Results for “OLFACTORY NERVE”

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At least 1,117 records · Page 62Linked to original sources
PubMed1979

Mechanisms of augmented field potential responses in the rat olfactory bulb.

Olfactory bulb field potential and single unit responses to paired pulse stimulation of the lateral olfactory tract were observed in the rat. In agreement with previous reports, surgical levels of barbiturate anesthesia prolonged the period of diminution of the field potential responses to the test pulse relative to the effect seen under light anesthesia. Very deep barbiturate anesthesia (sufficient to depress the EEG) led to decreased responses to the primary pulse but augmented responses to the test pulse. Urethane and ether anesthesia produced augmented test responses without severely depressing the EEG and without producing a period of diminished test responses. Single unit recordings failed to show external plexiform layer units excited at the time of maximal augmentation of the field potential. Simultaneous single unit and field potential recordings showed that prolonged diminution of the field potential response was associated with prolonged suppression of unit responses to the test pulse, while augmented field potential responses were associated with decreased suppression of unit responses to the test pulse. These observations are most easily explained by the assumption of temporal facilitation in the synaptic output of mitral and tufted cells. This facilitation is masked by feedback inhibition under some conditions, particularly under barbiturate anesthesia.

Anesthesia, General↗
PubMed1984

Selective retrograde transport of tritiated D-aspartate from the olfactory bulb to the anterior olfactory nucleus, pyriform cortex and nucleus of the lateral olfactory tract in the rat.

After an injection of [3H]D-aspartate into the olfactory bulb of the rat, retrogradely labeled cells were detected bilaterally in the anterior olfactory nucleus (AON), and ipsilaterally in the pyriform cortex (PC) and nucleus of the lateral olfactory tract (NLOT). These results suggest a certain selective retrograde transport of this amino acid, and are discussed in relation to transmitter candidates in the olfactory bulb.

Animals↗
PubMed1984

Topographic coding of odorant quality is maintained at different concentrations in the salamander olfactory epithelium.

In a recent study in the tiger salamander, Ambystoma tigrinum, were demonstrated topographic patterns of responsivity across the olfactory epithelium which were characteristic for each odorant. The present study was initiated to investigate whether these patterns remain constant when odorant concentration is varied. Odorant-induced electro- olfactograms were recorded from at least 12 sites on each epithelium. The odorants used were pinene, amyl acetate and propanol. Each epithelium was tested with one odorant, delivered at 3 concentrations. For comparison between animals, the epithelia were divided into 3 regions with at least 4 recording sites per region. An analysis of variance model was used to study odorants, concentrations, regions and animals. Odorant-induced regional patterns in responsivity were similar across all concentrations. In particular, the region of highest responsivity at one concentration was the region of highest responsivity at all concentrations. It is concluded that topographic patterns of receptor cell responses may reflect an underlying genetic component in the distribution of receptor cells. This distribution is related to two aspects of receptor cell responses: responsivity to particular odorants (Fig. 4) and general responsivity to all odorants (Fig. 5).

Ambystoma↗
PubMed1985

Distribution of calpain I, an enzyme associated with degenerative activity, in rat brain.

The calcium-activated protease calpain I was localized in rat brain by immunocytochemistry. Calpain I-like immunoreactivity (CLI) was prominent in several structures in which degeneration is an ongoing feature, e.g. spinal motoneurons, olfactory nerve. Also noteworthy was the presence of CLI in regions susceptible to age-related pathologies, e.g. cerebellar Purkinje cells, substantia nigra and subiculum. This distribution suggests that calpain I may be involved with both normal and pathological neuronal degeneration.

Animals↗
PubMed1986

Intracellular recordings from salamander olfactory supporting cells.

Stable intracellular potentials were recorded just below the surface of the salamander olfactory epithelium. The site of recording corresponded to the zone of highest density of supporting cell perikarya. The electrophysiological properties of cells recorded in this zone included: neither spontaneous nor evoked spike activity, high resting potential (-96 +/- 10 mV, n = 113) and low input resistance (15 +/- 12 M omega, n = 64). The cells were depolarized to -9 +/- 8 mV when the extracellular potassium concentration was increased from 2 to 100 mM. The membrane potential also changed during activation of the olfactory receptor neurons. Antidromic stimulation of olfactory axons elicited both rapid and slow depolarizations. Odorant stimulation induced graded depolarizations which always lagged behind the electro-olfactogram by more than 1 s. In contrast to the responses of the olfactory receptor neurons, these responses were nearly identical from one cell to another. Compared with the concomitant electro-olfactogram, they had almost the same amplitude, with a reversed polarity. These findings are discussed in the context of the possible auxiliary functions of supporting cells in olfactory processes.

Animals↗
PubMed1990

Olfactory but not vomeronasal mediation of scent marking by male golden hamsters.

Although olfactory and vomeronasal projections to the olfactory bulb and to the rest of the brain are quite distinct, it is not clear how the functions of these two chemosensory systems differ. In these experiments we attempted to determine the roles of the main olfactory and vomeronasal sensory systems in mediating scent marking by male golden hamsters, a behavior known to be stimulated by odors of other hamsters. Lesions of the main olfactory mucosa by irrigation of the nasal cavity with a solution of zinc sulfate dramatically reduced the frequency of marking. The degree of reduction in marking was correlated with an independent test of ability to detect volatile odorants. In contrast, surgical removal of the vomeronasal organ had no effect on marking frequency. Thus scent marking by male hamsters is primarily mediated by the main olfactory system and does not require the presence of the vomeronasal system. These results are discussed in the context of a theory that stresses the importance of the main olfactory system in pattern recognition and, in particular, in many types of social recognition.

Animals↗
PubMed1990

Inhibitory effects of centrally and peripherally induced anosmia on mounting behavior in the female rat.

Adult ovariectomized female rats received a testosterone-propionate (TP)-filled silastic implant and were tested for mounting behavior seven days later. Exposure to estrous female urine but not to urine from ovariectomized females increased the number of TP-treated females that displayed mounting behavior. Olfactory bulb removal on its own and peripheral anosmia induced by intranasal ZnSO4 application impaired mounting behavior. These results are discussed with respect to the effects of anosmia on copulatory behavior in the male.

Animals↗
PubMed1991

Interactions of testosterone with the olfactory system in the display of mounting behavior in the female rat.

Adult ovariectomized female rats received a testosterone propionate (TP) silastic implant (day 0) and were subsequently tested for mounting behavior. The number of females displaying mounting behavior increased from day 2 (0%) to day 14 (94%) following testosterone implantation. Olfactory bulbectomy (OB) performed on day -7 or on day +14 reduced the number of females that mounted on day +16 as compared to sham counterparts. However, the number of females displaying mounting behavior was significantly higher when OB was performed on day +14 than on day -7. Peripheral anosmia induced by ZnSO4 instillation, either with multiple instillations beginning on day -8 before TP implant or with a single injection on day +14, equally impaired mounting behavior on day +16. These results, which further confirm the role of the olfactory system in facilitating the display of mounting behavior in the female rat, suggest an olfaction-testosterone interaction.

Animals↗