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Biomedical subjects

G Whitney

Publications and source records attributed to G Whitney.

At least 37 records · Page 2Linked to original sources
PubMed1989

A method for isolating and patch-clamping single mammalian taste receptor cells.

Individual taste receptor cells were isolated from the tongue of the mouse by enzymatic treatment followed by mechanical dissociation. The cells were morphologically identical with taste cells from amphibians. Whole-cell voltage-clamp recordings indicated that the murine taste cells possess a variety of voltage-dependent inward and outward currents. Delayed rectifier currents were blocked by denatonium benzoate, one of the most bitter compounds known. This preparation should permit a detailed electrophysiologcal investigation of taste transduction in mammals at the level of taste receptor cells.

Animals↗
PubMed1989

Sucrose octaacetate-taster mice have more vallate taste buds than non-tasters.

Taste buds were counted in two strains of mice which have been characterized in terms of their taste avoidance of the bitter-tasting substance, sucrose octaacetate (SOA). One strain (SWR/J) avoids SOA and is referred to as "taster' while the other strain (C57BL/6J) does not avoid SOA at the same concentration and is termed "non-taster'. The taster-strain contains a significantly greater number of taste buds in its vallate papillae than the non-tasters do. The relative number of taste buds which individual mice and humans possess probably contributes to the relative differences in their sensitivity and preference behaviors.

Animals↗
PubMed1989

The B6.SW bilineal congenic sucrose octaacetate (SOA)-taster mice.

SWR/J inbred mice (Tasters) reliably avoid, whereas C57BL/6J inbred mice (Nontasters) are indifferent to, sucrose octaacetate (SOA) at certain concentrations. From these strains we have developed a set of bilineal congenic Taster mice. Approximately 4000 mice, from 2 isogenic and 12 segregating generations, were tested in a program designed to evaluate genetic models for SOA tasting during development of congenic strains. The criterion phenotype was avoidance or nonavoidance in preference tests of the bitter tastant SOA at concentrations of 10(-4) and 10(-5) M. Across the 12 segregating generations, the results were consistent with Mendelian expectations for a single autosomal locus with complete dominance of the Taster phenotype. The breeding program produced 12 replicate B6.SW lines containing the taster allele on the B6-Nontaster genomic background. The congenic Taster mice may facilitate a functional analysis of the sense of taste.

Animals↗
PubMed1989

Sucrose octaacetate tasting in a heterogeneous population of CFW mice.

Three experiments investigated the genetic underpinnings of the sucrose octaacetate (SOA) avoidance-indifference dimorphism that exists among outbred CFW mice. In the first experiment, results from 687 subjects across three generations of segregation were consistent with predictions from a single-autosomal, two-allele model, with dominance for the avoidance (Taster) phenotype. In the second experiment, heterogeneous CFW Tasters and Nontasters were mated with SWR/J (Taster) and C57BL/6J (Nontaster) inbred mice. The SWR and CFW mice are both derived from Swiss mice, and the results were consistent with the possibility that the Taster animals share an allele which is identical by descent. The second and third experiments also investigated sensitivity to SOA across an extended range of concentrations. Nontaster CFWs avoided SOA at the near-saturation 10(-3) M concentration but did not avoid any weaker concentrations. Taster CFWs avoided all concentrations down to approximately 10(-6) M SOA.

Alleles↗
PubMed1986

Neuropeptide routing in the bag cells: kinetic differences in the appearance of newly labeled peptides in transport and secretion.

The bag cell neurons of Aplysia synthesize and secrete several peptides. Some of these, in addition to the egg-laying hormone (ELH), are strongly implicated in the various alterations of central neuronal activity that accompany an electrical discharge of the bag cells. Thus, the secreted peptides appear to play a variety of roles in the animal's physiology. We have been interested in the intracellular mechanisms that precede peptide secretion from the bag cells because of the evidence that most, if not all, of these peptides are derived from a common precursor. Our objective has been to determine if presumed products of this precursor are processed coordinately following their synthesis. We have concentrated on two peptides (ELH and the acidic peptide, AP) because they are most easily identified in our analytical systems. On pulse-chase radiolabeling of the cells in vitro, we found that labeled AP appears before labeled ELH in axonal transport. This observation is not easily accounted for by the assumption, taken from studies of other peptide-secreting cells, that a precursor to both peptides is loaded into secretory granules before further processing ensues. Since the initial disproportion in the representation of the peptides in transport is no longer detectable at long chase times (18 and 24 hr), we examined the possibilities that ELH production is delayed relative to that of AP or that AP is degraded more rapidly than ELH. No evidence was found for either process. The disproportion between the newly labeled peptides in transport was evident on analysis of the medium bathing bag cells depolarized after 24 hr of chase.(ABSTRACT TRUNCATED AT 250 WORDS)

Axonal Transport↗
PubMed1985

Ultrasonic vocalizing by adult female mice (Mus musculus).

Though an extensive body of literature exists concerning the emission of 70-kHz ultrasonic vocalizations by adult male mice (Mus musculus), almost nothing is known about the ultrasonic vocalizing of adult females. A series of five experiments was conducted to examine adult female mouse ultrasound emission. Results indicated female ultrasonic vocalizing to be typically displayed among female mouse dyads and comparable to the ultrasonic vocalizing levels obtained among male-female pairs. Genotypically based variations in the production of ultrasounds by females were also noted. Like male mice, socially naive females readily ultrasonically vocalized to anesthetized female conspecifics and rarely vocalized to anesthetized males. Unlike males, socially experienced females emitted few ultrasounds to either female urine or female-soiled cage shavings. Although social experience served to increase the ultrasound emission of male mice to female sex cues, the production of ultrasounds by females to these cues was decreased by social experience. Implications with regard to the existence of a behavioral/functional sexual dimorphism in adult mouse ultrasonic vocalizing are discussed.

Animals↗
PubMed1983

Experience-based vocalization of male mice to female chemosignals.

Previous experimentation led to a suggestion that pituitary-mediated metabolites present in female urine are important determinants of stimulus potency in eliciting 70 kHz ultrasonic vocalizations from adult male mice (Mus musculus). In the present experiment this hypothesis was reexamined, taking into account the prior experience of the male test subjects. Male mice were given social experience with either hypophysectomized females or intact, normal females and were then monitored for ultrasonic vocalizations to chemosensory stimuli from both. Results indicated that males (1) will emit ultrasonic vocalizations to urine from hypophysectomized females and (2) tend to preferentially emit ultrasound to stimuli from the type of female previously encountered during the social experience regimen. It is proposed that the previously reported lack of ultrasound emission by males to chemosignals from hypophysectomized females can be accounted for via straightforward associative learning mechanisms.

Animals↗
PubMed1982

The vomeronasal organ: primary role in mouse chemosensory gender recognition.

Four experiments were conducted to determine the chemosensory modality that supports ultrasonic courtship vocalizations by male mice to females and to chemosignals from females. Both removal of the olfactory bulbs (Experiment 1) and removal of the vomeronasal organ (Experiments 2-4) produced similar deficits in the pattern of ultrasonic vocalizations elicited by conspecifics or their odors. Removal of the vomeronasal organ did not impair the ability to locate food buried under cage shavings. These results are consistent with the notion that the analysis of food related odors is subserved by olfaction and that vocalizations to sex chemosignals are elicited primarily by stimulation of the vomeronasal organ/accessory olfactory bulb. Removal of the vomeronasal organ did not induce seminal vesicle regression or lower plasma immunoreactive testosterone levels (Experiment 2) nor was an attempt to restore vocalizations with exogenous testosterone successful (Experiment 4). Thus the altered vocalization pattern following removal of the vomeronasal organ does not appear to arise as a motivational deficit mediated by androgens. Experiments 2 and 3 demonstrated that, in the absence of the vomeronasal organ, stimulation of other sensory systems can, to some extent, maintain the male's tendency to vocalize more to females or their odors than to males or their odors. However, this responsiveness to females may rely upon additional behavioral cues. Previous experience also plays a considerable role in the response to chemosensory gender cues by males who lack their vomeronasal organs. Removal of the vomeronasal organ prior to adult heterosexual encounters (Experiment 3) virtually eliminated the male's responsiveness to either anesthetized females or their chemosignals. Hence males require adult heterosexual experience with a functioning vomeronasal organ before other chemosensory systems acquire the ability to mediate gender recognition as measured by ultrasonic vocalizations.

Animals↗
PubMed1981

Stimuli for male mouse (Mus musculus) ultrasonic courtship vocalizations: presence of female chemosignals and/or absence of male chemosignals.

In research on animal chemocommunication, biological odors are sometimes presented by being applied to a "neutral" animal (e.g., castrated or ovariectomized conspecific). This technique is typically utilized when the behavioral response to the odor requires the presence of a conspecific. In five experiments, mice (Mus musculus) that might be expected to be neutral stimuli were examined for their abilities to elicit ultrasonic courtship vocalizations from male mice. Paradoxically, adult castrated males, adult males that were neonatally castrated, hypophysectomized males, prepubertal females, and hypophysectomized females all elicited more vocalizations than would have been predicted from previous research in which their urine alone was used as the stimulus. These and previous results are consistent with courtship vocalizations being promoted by chemosignals from females and/or by an absence of cues from males. Thus a truly neutral conspecific for presenting female sex odors may not exist in mice.

Animals↗
PubMed1978

Genotype and test experience determine responsiveness to morphine.

Initial responsiveness to morphine was studied in two inbred strains of mice, C57BL/6J and DBA/2J, and their F1 hybrid, using both a hot-plate analgesia test and a locomotor-activity test. Three dose levels of morphine were used, 0 mg/kg 5 mg/kg, and 15 mg/kg. The inclusion of the 0 mg/kg group revealed differences between the inbred strains in the effects of test experience. These data also led to some new conclusions about the differences in responsiveness to morphine between the strains studied. On both tests, the DBA mice showed no effect of morphine, the C57 mice showed large effects, and the F1 mice showed an intermediate effect.

Analgesics↗