Integrative peptides

Angiotensin and CCK are presented as examples of neuropeptides that might function in the body and the brain as hormones and neurotransmitters to integrate physiological functions with psychological functions. It is suggested that they be called, integrative peptides, to distinguish them from the more limited functions, or less well documented functions, of the other regulatory peptides.     

Randomized trial of umbilical arterial catheter position: clinical outcome

In order to determine if umbilical arterial Catheter position affects the incidence of necrotizing enterocolitis, clinical outcome was analysed in 308 infants whose umbilical arterial catheter had been randomly allocated to a high ( n =162) or a low ( n =146) position. Necrotizing enterocolitis was classified as suspected or confirmed; all renal, lower limb and local catheter complications were also recorded. High umbilical arterial catheters were in place for longer than low catheters, provided more samples and were removed as an emergency less often. Lower limb blanching and cyanosis were more common with low catheters. Eleven cases of confirmed necrotizing enterocolitis occurred in the "high" group and nine in the "low" group. One case of fatal aortic thrombosis was encountered in the high group. Positioning umbilical arterial catheters in a high position allowed longer functional use and did not increase the incidence of necrotizing cnterocolitis.     

Hyperphagia following intraventricular p-chlorophenylalanine-, leucine- or tryptophan-methyl esters: Lack of correlation with whole brain serotonin levels

The methyl ester hydrochlorides of DL-p-chlorophenylalanine (PCPA), L-leucine and L-tryptophan were intraventricularly administered to rats. All compounds produced increased food intake compared to saline administration. PCPA and leucine administration significantly decreased serotonin levels by 15–18%, while no serotonin depletion occurred following tryptophan injections. The data suggest that intraventricular injections of large quantities of neutral amino acid methyl esters may cause hyperphagia in rats through non-serotonergic effects on brain function.     

Aversive hypothalamic stimulation releases acetylcholine in the nucleus accumbens, and stimulation-escape decreases it

Hypothalamic electrodes can generate positive reinforcement, as shown by self-stimulation, and negative reinforcement shown by stimulation-escape. It was hypothesized that acetylcholine (ACh) is released in the nucleus accumbens during the aversive state that underlies stimulation-escape. If this is correct, escape behavior should lower extracellular ACh. Rats were prepared with microdialysis probes in the accumbens (posterior shell region) and electrodes in the perifornical lateral hypothalamus. Animals learned to press a lever for 0.5 s trains of stimulation (typically 3600 responses/h). Then they were given automatic stimulation to determine which animals would also learn to press a lever to turn stimulation off for 5 s at a time (typically 75 responses/h). Accumbens microdialysis showed that automatic stimulation caused extracellular ACh to double, but only in the rats that were motivated to learn stimulation-escape. When allowed to escape stimulation, these animals lowered extracellular ACh significantly. It is concluded that ACh release in the accumbens is related to the neural state that animals work to escape.