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Biomedical subjects

H V Peeke

Publications and source records attributed to H V Peeke.

49 records · Page 3Linked to original sources
PubMed1971

Caudate nucleus stimulation retroactively impairs complex maze learning in the rat.

Rats, with permanent electrodes implanted bilaterally in the caudateputamen complex, were stimulated with single pulses after reinforcement of each maze learning trial or were stimulated with multiple pulses after each choice point or after reinforcement. Single pulses retarded the development of learning only when stringent learning criteria were required, whereas multiple pulses interfered with acquisition when the criteria for learning were less difficult.

Age Factors↗
PubMedDate not supplied

Alcohol, habituation and the patterning of aggressive responses in a cichlid fish.

Territorial cichlids were presented for 30 min with a conspecific male intruder (contained in a clear glass tube). Eight hr prior, 2 groups were administered alcohol (0.15 or 0.30 percent in the aquaria water). A third group served as a control. Three responses were recorded to allow analysis of topographic changes in behavior as well as changes in absolute levels. During the habituation phase, the normal group showed a sequence of long displays, followed by shorter ones as the frequency of attacks increased. The occurrence of threat which gradually gives way to attack is characteristic of the agonistic behavior of this species. In contrast to the controls, the 0.15 percent group was hyperaggressive, while the 0.30 percent group was hypoaggressive. Furthermore, the patterning of responses were abnormal. The 0.15 percent group gave abbreviated threats and more attacks (interpreted as a tendency to attack without warning); whereas, the 0.30 percent group gave many long threat displays, but few attacks. A stimulus specificity test provided strong evidence that the waning found during the initial phase was habituation.

Aggression↗
PubMedDate not supplied

Bioassayable cholecystokinin in the brain of the goldfish, Carassius auratus.

Cholecystokinin (CCK)-gastrin peptides are shown to be present in the brain of all the species ranging from coelenterates to mammals. Differentiation between CCK and gastrin, presumed to be evolved from a common ancestral cerulein-like peptide, has been suggested to occur at the level of the amphibians. We examined the presence of bioassayable CCK, as determined by its potency to stimulate enzyme secretion from isolated rat pancreatic acini, in the brain of the goldfish Carassius auratus, a more primitive vertebrate than the amphibian. Among the various regions tested, the brain stem, telencephalon and spinal cord possess the highest levels of bioassayable CCK followed in decreasing order by gustatory lobes, optic tectum and duodenum. No detectable levels of CCK were found in the cerebellum. The observed bioactivity was not due to gastrin because: radioimmunoassay of the brain homogenates for gastrin revealed very low or nondetectable levels of gastrin; amylase release dose-response curves for standard CCK8 and the brain homogenate were identical; and proglumide, a competitive antagonist of CCK8, inhibited homogenate CCK-induced enzyme release with a parallel rightward shift in the dose-response curve. These observations provide evidence for the distinct presence of CCK in the brain of the goldfish suggesting that the differentiation of CCK as a distinct neuropeptide, from that of gastrin, occurs at the level of Osteichthyes (bony fish).

Amino Acid Sequence↗