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Digitale Medien

Aggression and risk assessment during predatory interactions between first-instarSinea diadema (Fabricius) (Hemiptera: Reduviidae) (1994)

Taylor, J. R. ; Schmidt, J. M.

Springer

Journal of insect behavior 7 (1994), S. 297-311

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ISSN: 1572-8889

Schlagwort(e): Reduviidae ; intraspecific interactions ; cannibalism ; predation

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract The behaviors exhibited by first-instarSinea diadema (F.) (Hemiptera: Reduviidae) during intraspecific interactions are described. Five distinct behaviors were characterized: posturing, striking, stalking, stridulating, and beaking. Distinct bouts of grappling were also noted. Interactions between unfed 2-day-old nymphs, unfed 3-day-old nymphs, and unfed 5-day-old nymphs were recorded and analyzed. The behavior of the nymphs changed with the duration of food deprivation. As the period of food deprivation increased from 2 to 5 days, the frequency of posturing decreased as the frequency of beaking increased. During noncannibalistic interactions, posturing or striking by one nymph was most frequently followed by posturing by the other nymph. In contrast, during cannibalistic interactions, posturing or striking was usually followed by beaking. The incidence of grappling increased with the duration of food deprivation. Moreover, grappling always preceded cannibalism. Although first instars were capable of capturing and killing conspecifics of the same age, cannibalism occurred only after 4 days of food deprivation. These results suggest that a decision-making process is involved. During interactions the nymphs can assess the vulnerability of the opponent. Whereas recently emerged nymphs usually forego the risk of attacking conspecifics, the attacks made by nymphs deprived of food are more persistent despite the danger of predation by their opponent.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01989737

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Digitale Medien

Grafting of fetal substantia nigra to striatum reverses behavioral deficits induced by MPTP in primates: a comparison with other types of grafts as controls (1991)

Taylor, J. R. ; Elsworth, J. D. ; Roth, R. H. ; [weitere]

Springer

Experimental brain research 85 (1991), S. 335-348

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ISSN: 1432-1106

Schlagwort(e): MPTP ; Graft ; Behavior ; Parkinson's disease ; Monkey

Quelle: Springer Online Journal Archives 1860-2000

Thema: Medizin

Notizen: Summary Fetal substantia nigra (SN) cells were transplanted into the caudate nucleus (CN) of four vervet monkeys (Cercopithecus aethiops sabaeus) that had been treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP treatment appears to produce a syndrome similar to that observed in patients with idiopathic Parkinson's disease. Normal and parkinsonian behaviors were quantitated by trained observers 5 days/week. Twenty-eight behaviors based on previous factor analyses were individually scored and rated. Parkinsonian signs included freezing, head and limb tremor, difficulty in eating, delayed initiation of movement, poverty of movement, tremor that stopped with intention, decreased response to threats, and lying immobile in the cage. These signs were combined to give an overall rating of parkinsonism. A summary measure of ‘normal’ healthy behavior was also examined, including such behaviors as yawning, scratching, self-grooming, shifting, and eating. Overall ratings of parkinsonism increased and those of healthy behavior decreased after MPTP. In the 4 monkeys grafted with fetal SN cells into the CN, behavior returned to pre-treatment levels by the time of sacrifice (2, 5, or 7.5 months after grafting). Three control subjects were transplanted with either SN cells into an inappropriate brain site (cortex) or inappropriate, non-dopaminergic, cells (cerebellar) into the CN. Subjects were also compared with three control animals that did not receive MPTP but received cryopreserved or fresh SN and other cells into the CN. Only MPTP-treated subjects that received SN cells into the CN showed evidence of a reversal of the MPTP syndrome after transplantation. In addition, grafting in animals that were not MPTP-treated did not appear to affect behavior. This paper reports the specific behavioral effects of severe MPTP toxicity that were or were not reversed after transplantation and suggests that only fetal SN cells grafted into the CN may be able to reverse behavioral deficits in MPTP-treated monkeys.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00229411

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Digitale Medien

Yohimbine co-treatment during chronic morphine administration attenuates naloxone-precipitated withdrawal without diminishing tail-flick analgesia in rats (1991)

Taylor, J. R. ; Lewis, V. O. ; Elsworth, J. D. ; [weitere]

Springer

Psychopharmacology 103 (1991), S. 407-414

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ISSN: 1432-2072

Schlagwort(e): Yohimbine ; Morphine ; Naloxone ; Withdrawal ; Tail flick latency ; Rat

Quelle: Springer Online Journal Archives 1860-2000

Thema: Medizin

Notizen: Abstract Noradrenergic neuronal hyperactivity following chronic morphine administration has been postulated to cause withdrawal signs and symptoms. Suppression of this hyperactivity, for example, by clonidine attenuates withdrawal. It might follow, therefore, that the prevention of suppression of noradrenergic systems during chronic morphine administration might diminish hyperactivity and prevent withdrawal. If the normalization of noradrenergic activity during opioid administration did not also suppress analgesia, it might be of medical and theoretical interest. To test this hypothesis, we gave the alpha-2-antagonist yohimbine to rats in order to increase noradrenergic activity during morphine treatment and then subsequently precipitated morphine withdrawal with naloxone. Six groups were examined: saline controls (N=11), morphine (N=11), morphine + 2.0 mg/kg/day yohimbine (N=15), morphine + 3.0 mg/kg/day yohimbine (N=5), 2.0 mg/kg/day yohimbine (N=11) and 3.0 mg/kg/day yohimbine (N=5). Subjects received 75 mg morphine pellets implanted on day 1,4 and 6 of the treatment or sham implantation. Yohimbine was delivered throughout the morphine treatment by subcutaneously implanted osmotic pumps. On day 7, all subjects were given 1.0 mg/kg naloxone and rated for behavioral signs of withdrawal. Analgesia was measured by observing tail flick latencies (TFL) before and after chronic drug treatments. Naloxone-precipitated withdrawal was characterized by irritability, ptosis, penile erection, diarrhea, rhinorrhea, abnormal posture, wetdog shakes, jumping, and teeth chattering, none of which were observed in groups receiving only saline or yohimbine. Withdrawal behavior was attenuated in a dose-dependent manner when yohimbine was administered during morphine treatment but analgesia was not attenuated. It appears that yohimbine-induced antagonism of alpha-2-adrenergic receptors diminishes the development of the potential for adrenergic hyperactivity and morphine withdrawal without reducing opioid analgesia.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF02244297

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Digitale Medien

Potentiation of the effects of reward-related stimuli by dopaminergic-dependent mechanisms in the nucleus accumbens (1991)

Cador, M. ; Taylor, J. R. ; Robbins, T. W.

Springer

Psychopharmacology 104 (1991), S. 377-385

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ISSN: 1432-2072

Schlagwort(e): Conditioned reinforcement ; Dopamine ; Noradrenaline ; d-Amphetamine ; Dorsal noradrenergic bundle ; Nucleus accumbens

Quelle: Springer Online Journal Archives 1860-2000

Thema: Medizin

Notizen: Abstract Three experiments examined the behavioural, pharmacological and neural specificity of the previously reported potentiation of responding with conditioned reinforcement following intra-accumbensd-amphetamine, by studying the effects of intraaccumbens dopamine (DA) and noradrenaline, using an acquisition of a new response procedure. In experiment 1, the effects of intra-cerebral DA infusions (5, 20, 50 µg/2 µl) were compared in four conditions: (i) intra-accumbens DA following positive pairing of the conditioned stimulus (CS) and water during training; (ii) as (i) but also following a systemic dose of the DA receptor antagonist alpha-flupenthixol; (iii) intra-accumbens DA following random pairing of the CS and water during training; and (iv) as (i) but with intra-caudate rather than intra-accumbens DA. The results showed that only with intra-accumbens DA in the positive pairing condition was there a significant dose-dependent increase in responding. In experiment 2, the effects of a higher range of doses (20, 100, 200 µg) and smaller infusion volume (5, 25, 50 µg/l µl) of intra-accumbens DA were studied, in comparison with a similar range of doses (5, 25, 50 µg/l µl) of intra-accumbens noradrenaline (NA). Only DA produced a selective, dose-dependent increase in responding with conditioned reinforcement. In experiment 3 neurotoxic lesions of the dorsal noradrenergic bundle (DNAB) using 6-hydroxydopamine producing profound (about 90%) depletion of cortical and nucleus accumbens NA levels had no effect on the increased responding with conditioned reinforcement produced by intra-accumbensd-amphetamine (3, 10, 30 µg/l µl). The results are discussed in terms of the neurochemical mediation of the potentiation of the effects of conditioned reinforcers byd-amphetamine and the role of DA-dependent mechanisms of the nucleus accumbens in reward-related processes.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF02246039

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