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K Delaney

Publications and source records attributed to K Delaney.

29 records · Page 2Linked to original sources
PubMed1991

Opiate agonists activate feeding in Limax: comparison of in vivo and in vitro effects.

The neural control system for feeding in the terrestrial mollusc Limax maximus is modulated by at least two major families of peptides. Sequence homology between one of the peptides known to modulate Limax feeding and some members of the opioid peptide family suggested that opioid peptides might also modulate Limax feeding. Experiments with the mu agonist morphine and the kappa agonist U50,488H showed that the probability of feeding, but not meal size, was increased by morphine injection into intact animals, whereas the length of feeding motor program responses elicited from the isolated lip-brain preparation of Limax was augmented by U50,488H. The behavioral effect of morphine was blocked by naltrexone injection, whereas the physiological effect of U50,488H was blocked by naloxone. Factors that influence the behavioral and electrophysiological effects of opioids on mollusc feeding are discussed.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1991

Presynaptic calcium and serotonin-mediated enhancement of transmitter release at crayfish neuromuscular junction.

Fura-2 microfluorometric measurements of calcium concentrations in excitor motor nerve terminals of the first walking leg of crayfish Procambrus clarkii were made during application of serotonin (5-HT) to examine whether changes in residual calcium concentration or calcium influx are responsible for the 5-HT-induced increase in transmitter release at this synapse. Calcium concentrations and EPSPs were monitored simultaneously during 0.5-Hz and moderate-frequency (3-16 Hz) stimulation before, during, and after a 5-min application of 5-HT at concentrations between 5 and 100 microM. We did not observe a significant increase in resting calcium concentration [Ca2+]i in presynaptic terminals during or after application of 5-HT despite simultaneously recorded excitatory junction potential (EJP) enhancement. Injection of the calcium buffer EGTA to concentrations sufficient to reduce significantly the buildup of frequency-dependent facilitation during trains of action potentials did not reduce 5-HT-mediated EJP enhancement. We therefore conclude that 5-HT does not release calcium from intracellular stores to an extent sufficient to overcome calcium buffering and removal systems. Spontaneous release of transmitter quanta was increased by 5-HT to the same extent in normal and increased-osmolarity saline in the absence of measured changes in [Ca2+]i. Thus, changes in residual calcium cannot explain 5-HT-induced synaptic enhancement. Increasing the action-potential-mediated calcium influx by broadening the spike or by increasing extracellular calcium increased evoked transmitter release and increased the accumulation of calcium during trains of action potentials. However, though 5-HT produced a comparable synaptic enhancement, we found no evidence for increased calcium accumulation during trains of action potentials, suggesting that net calcium influx, buffering, and removal are not affected by 5-HT. Therefore, we conclude that 5-HT's action does not result from effects on calcium metabolism and suggest that it acts on the neurosecretory apparatus to increase the effectiveness of calcium for stimulating release. Furthermore, based on its relatively constant effects on facilitated and unfacilitated action-potential-evoked release and spontaneous transmitter release, we conclude that 5-HT actions are independent of the concentration of calcium that is driving release.

Action Potentials↗
PubMed1988

A method for reproducing fatal idiopathic colitis (colitis X) in ponies and isolation of a clostridium as a possible agent.

Severe colitis was induced in two ponies after oral pretreatment with clindamycin and lincomycin, followed by intestinal content from two horses which had died from naturally-occurring idiopathic colitis. Two ponies treated with antibiotic alone, and two ponies treated with intestinal content alone, were unaffected. In a further study, three ponies treated on separate occasions with lincomycin, administered orally, died or were destroyed 67 to 72 h after initial treatment. No established salmonella, yersinia or campylobacter pathogens were isolated from these ponies, but a clostridium closely resembling Clostridium cadaveris was isolated as the predominant clostridium from them all and from the colonic content of one of six horses which died from naturally-occurring idiopathic colitis. It was not isolated from six horses with non-fatal diarrhoea. This clostridium is a candidate as an agent of some cases of fatal colitis in horses.

Animals↗
PubMed1987

Acetylcholine activates cerebral interneurons and feeding motor program in Limax maximus.

The cellular and network effects of acetylcholine (ACh) on the control system for feeding in Limax maximus were measured by intracellular recordings from feeding command-like interneurons and whole nerve recordings from buccal ganglion motor nerve roots that normally innervate the ingestive feeding muscles. The buccal ganglion motor nerve root discharge pattern that causes rhythmic feeding movements, termed the feeding motor program (FMP), was elicited either by attractive taste solutions applied to the lip chemoreceptors or by ACh applied to the cerebral ganglia. The ability of exogenous ACh applied to the cerebral ganglia to trigger FMP was blocked by the cholinergic antagonists curare and atropine. If the strength of the lip-applied taste stimulus was in the range of 1-2 times threshold, cerebral application of the cholinergic antagonists blocked or greatly decreased the ability of lip-applied taste solutions to trigger FMP (5 of 8 trials). The cerebral feeding interneurons, some of which activate FMP when stimulated intracellularly, are excited by small pulses of ACh applied directly to the cell body from an ACh-filled micropipette. A pulse of ACh that activates several of the feeding interneurons simultaneously triggers FMP. The data suggest that under certain stimulus conditions an obligatory set of cholinergic synapses onto the feedininterneurons must be activated for taste inputs to trigger ingestion. The determination of ACh's action within the feeding control system is necessary for understanding how enhanced cholinergic transmission leads to prolonged associative memory retention (Sahley, et al., 1986).

Acetylcholine↗
PubMed1986

Post-ingestive food-aversion learning to amino acid deficient diets by the terrestrial slug Limax maximus.

An agar-based artificial diet containing carbohydrates, fats and twenty amino acids was constructed. This diet is highly palatable and nutritionally complete for Limax maximus as demonstrated by significant ingestion on first encounter, consistent ingestion on subsequent days and good growth of young slugs fed this diet. Removing methionine, an essential amino acid, from the complete diet produces a food which is initially as palatable as the complete diet, but after one day's intake the amount of this deficient diet eaten is greatly reduced. Removing alanine, a nonessential amino acid, does not produce any decrement in feeding relative to the complete diet. A single meal can be sufficient for establishing the aversion to the deficient diet. Following seven days of feeding on the deficient diet the aversion is retained with little or no attenuation for at least 30 days and does not generalize to either a known 'safe' food or a novel food. Evidence of a mild neophobia towards the artificial diet which attenuated after one or two meals was seen. The learned aversion to the deficient diet is reversible if slugs are repeatedly fed the complete diet following feeding on the deficient diet. Also, slugs initially fed the complete diet will develop an aversion to the methionine-deficient diet after sampling it. Slugs readily ate the artificial diets when these were offered 7 days post-hatch. The methionine-deficient diet however was not eaten in large amounts after the first meals and did not support growth. Baby slugs fed the methionine-deficient diet for 10 days and then maintained on rat chow ate only small amounts when the deficient diet was presented again 126 days later, while baby slugs fed the complete diet or an alanine deficient diet for 10 days ate large amounts when these diets were presented 126 days later. Supplementing the methionine-deficient diet with an injection of methionine into the haemocoel one hour after the completion of a meal completely blocks the development of a learned aversion while injection of Limax saline does not. These results are best explained by the hypothesis that the slugs acquire, post-ingestively, an aversion to the taste and probably the odor of the diet as the result of associative learning.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1983

Personal competence of institutionalized adult males with or without Down syndrome.

The Personal Competence Profile was administered to 30 male adults with Down syndrome and 30 male adults without Down syndrome matched on age, IQ, and years of institutionalization. Down syndrome subjects rated higher on attention, calmness, and niceness but lower on sensation, language, and boldness. The results were consistent with the classical personality stereotype of Down syndrome and suggest the utility of using personal competence as a framework for studying behavioral aspects of mental retardation.

Adult↗
PubMedDate not supplied

Time-out: an overused and misused milieu intervention.

TOPIC: The basic logic of the time-out, its conceptual underpinnings, its misuse in inpatient psychiatry, and suggestions for appropriate application. PURPOSE: In the inpatient treatment setting, time-outs can become an automatic response to any behavioral infraction. When this happens, time-outs begin to lose their effectiveness because the intervention does not necessarily address the child's needs or the underlying mechanisms of the inappropriate behavior. They also can be misused when time-outs escalate into a lengthy stay in a seclusion room. The author examines the dynamic underlying the misuse and overuse of the time-out. SOURCES: Personal observations and published literature. CONCLUSIONS: The time-out is a useful tool, but only when employed with minded intent and understanding of how it is supposed to help the child.

Behavior Therapy↗
PubMedDate not supplied

The development of a sunscreen.

Australians generally admire an evenly tanned skin, and the ability to acquire such a tan without much or any discomfort due to burning, is widely prized and envied. Various topical sunscreens have been introduced in order to facilitate the attainment of such a state, and this paper describes the stages in the development of such a product. The final product must obviously contain an active ingredient with the necessary selective filtering properties. This ingredient, and the vehicle in which it is presented, must be free of sensitising properties and must not cause acute or chronic toxic effects. Finally, it must be shown, under various typical conditions of use, to possess overall efficacy in terms of protecting from burning while permitting tanning.

Acute Disease↗