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Biomedical subjects

R Apfelbach

Publications and source records attributed to R Apfelbach.

15 recordsLinked to original sources
PubMed1987

Developmental patterns of thyroid hormones and testosterone in ferrets.

Plasma levels of thyroxine (T4) and triiodothyronine (T3) were measured in male and female ferrets at regular intervals between postnatal day 20 and 150 as well as in adult animals. In addition, testosterone level in male ferrets was measured. All hormones showed characteristic developmental patterns. There is a T4 maximum prior to a T3 maximum in subadult animals which in both cases surpasses adult levels. Testosterone level shows a different developmental pattern. There is an outstanding peak in subadult males around day 60-80, which, however, is surpassed by adult levels during the mating season.

Animals↗
PubMed1987

Effects of cyproterone acetate on mating behavior, testicular morphology, testosterone level, and body temperature in male ferrets in comparison with normal and castrated males.

Effects of surgical castration of 60-day-old male ferrets are compared with the effects of a chemical castration with cyproterone acetate from postnatal day 60 until 360. Investigations were made on mating behavior, intermale aggression, testicular morphology, plasma testosterone level and body temperature. While controls show seasonal variations in all parameters, according to the annual cycle of sexual activity and inactivity, both, surgically and chemically castrated ferrets show throughout the year constant parameters similar to that of controls during the sexual inactive period. All investigated effects of a long-term treatment with cyproterone acetate are fully reversible within 2 years after termination of drug administration.

Animals↗
PubMed1986

Changes in granule cells of the ferret olfactory bulb associated with imprinting on prey odours.

The maturation of the granule cells of the ferret olfactory bulb around the time of odour imprinting has been examined. Rapid Golgi impregnation studies revealed a temporal overshoot in the development of the spines on the external and internal dendrites of the granule cells. In contrast, the number of somatic spines decreased continuously. Electron microscopical examinations of the synaptic contacts in the external plexiform layer revealed that the time course of synapse and reciprocal synapse formation was similar to that of the formation of the spines on the external dendrites. The results were taken as evidence that both the Golgi and the electron microscopical investigations described the same developmental process of postnatal synaptic rearrangement.

Animals↗
PubMed1985

Olfactory deprivation enhances normal spine loss in the olfactory bulb of developing ferrets.

Ferrets show a sensitive phase in their postnatal development during which they can become imprinted to food odors. At the same time the number of granule cell spines in the olfactory bulb reaches a maximum, declining significantly thereafter. In ferrets, exposed continuously to saturated levels of geraniol odor in the cage environment, the normal decline in spine number (occurring between day 60 and 90) is significantly enhanced. No such effects were observed during earlier ontogenetic phases. This late postnatal phase is further associated with a marked and significant decrease in total brain weight. The significance of these events to olfactory imprinting and plasticity in the developing brain is discussed.

Acyclic Monoterpenes↗
PubMed1981

Instinctive predatory behavior of mustelids (Mustela putorius f. furo, Mustela vison f. dom.) modified by benzodiazepine derivatives.

The predatory behavior of the ferret and of the mink consists mainly of instinctive behavioral patterns that are elicited by simple external stimuli. An important stimulus is size of the prey; the time needed to catch and kill defensive prey depends on the size of the prey in relation to that of the predator. Benzodiazepine derivatives like chlordiazepoxide or lorazepam affect the prey catching of both species significantly. Drugged animals (2 mg/kg orally) need less time to overpower their prey. The experiments indicate that low concentrations of benzodiazepine derivatives disinhibit mustelids when hunting relatively large prey.

Animals↗
PubMed1978

Instinctive predatory behavior of the ferret (Putorius putorius furo L.) modified by chlordiazepoxide hydrochloride (Librium).

The predatory behavior of ferrets (Putorius putorius furo L.) consists mainly of instinctive behavioral patterns that are elicited by simple external stimuli. For the ferret, the time needed to catch and kill rats depends on the size of the rats in relation to that of the ferret. Killing success decreases with a relative increase in prey size. Chlordiazepoxide hydrochloride injections (1 mg/kg, i.m.) modified this behavior. Drugged ferrets needed less time and less bites to kill relatively large rats; killing success was also increased. Chlordiazepoxide seemed to disinhibit the ferrets when they were presented with large rats, which they normally attack more cautiously.

Animals↗
PubMed1977

[Psychopharmacological influence on the prey catching behavior of ferrets (Putorius furo L.) (author's transl)].

The prey-catching behavior of ferrets (Putorius furo L.) consists mainly of instinctive behavior patterns, which can be elicited only through their releaser. Then they are performed stereotypically. To get information concerning the central background and the hierarchical structure of this behavior the neuroleptics Haloperidol (0.14 mg/kg), Clozapine (10 mg/kg) and Chlorpromazine (4 mg/kg) were injected i.m. under controlled conditions. In a conditioning experiment the reactivity of the animals was examined. This conditioned reaction was strongly decreased by the drugs. The reaction to the natural stimulus the prey was changed, but not suppressed. The modification of the predatory behavior was manifedsted in an "improvement" of orientation reactions when pursuing the prey and in a better placement of bites. This effect, most evident with Haloperidol, is possibly due to the specific neuroleptic component of the substances. A delay in approaching the prey, or even the total suppression of the prey-catching behavior is suggested to be due to a sedative component which was most obvious in some experiments with Clozapine. On the other hand, there are behavioral elements like the use of paws which are not effected by the neuroleptics. From these and other observations, it is concluded, that the predatory behavior of the ferret has a hierarchically organisated structure. Further it is suggested that some functional connected parts of the behavior have distinct central representation, for they are not influenced in the same way by these drugs.

Animals↗