The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

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Although several recent anatomical and physiological studies indicate that glutamate receptors are likely to play a role in the regulation of various hypothalamic functions, no attempt has yet been made to specifically characterize glutamate receptor densities, subtypes, or localization in the hypothalamus. To provide this basic information, we have characterized and mapped the binding of [3H]glutamate to N-methyl-D-aspartate (NMDA), non-NMDA, and metabotropic glutamate receptors throughout the diencephalon. Membrane binding assays revealed a [3H]glutamate binding density of 2.6 pmol/mg protein, approximately one third of the hippocampal density. Binding of subtype-specific agonists and antagonists was complex, but clearly indicated that each major glutamate subtype is present in all hypothalamic and preoptic regions in the following approximate relative densities: NMDA > metabotropic Glu receptor > kainate > or = alpha-amino-3-hydroxy-5- methyl-4-isoxazolepropionic acid. Receptor autoradiography confirmed the widespread presence of all major glutamate receptor subtypes with roughly the following relative regional densities: ventromedial, dorsomedial > paraventricular, anterior hypothalamic, supraoptic > arcuate, suprachiasmatic, lateral hypothalamic > preoptic area >> pituitary neural lobe, white matter > pituitary anterior lobe (negligible). Subtype expression varied regionally, with rostral hypothalamic and preoptic regions having proportionally higher levels of non-NMDA vs. NMDA binding. High densities of glutamate receptors in ventromedial and medial hypothalamic regions suggest a prominent role in neuroendocrine and autonomic regulation.

SUMMARY1. In chronically-prepared sheep, intracranial temperatures were measured in the cavernous sinus among the vessels of the carotid rete and at the circle of Willis extravascularly, and in the preoptic area and in other brain stem regions. Extracranial temperatures were measured intravascularly in the carotid or internal maxillary arteries and on the nasal mucosa and the skin of the ear.2. At 20°C ambient temperature, shifts in temperature of the hypothalamus and of other brain sites paralleled temperature shifts in the cerebral arterial blood which was cooler than central arterial blood. During periods of arousal and of paradoxical sleep, vasoconstriction of the nasal mucosa and the ear skin occurred and temperatures at the cerebral arteries and in the brain rose without a comparable rise in central arterial blood temperature.3. Anaesthetic doses of barbiturate abolished the temperature oscillations in the cerebral arterial blood and the brain. When air was blown rapidly over the nasal mucosa in anaesthetized animals, temperatures dropped precipitously in the cavernous sinus, at the cerebral arteries, and in the brain, while central arterial temperature fell only slightly. Injections of latex into the facial venous system demonstrated a venous pathway from the nasal mucosa to the cavernous sinus.4. When sheep were exposed to 45-50°C ambient temperature, respiratory rate increased 5-10 times and the temperature gradient between central and cerebral arterial blood widened.5. It is concluded that venous blood returning from the nasal mucosa and the skin of the head to the cavernous sinus cools the central arterial blood in the carotid rete. This is an important factor in the maintenance of hypothalamic temperature in the wool-covered, long-nosed, panting * National Institutes of Health trainee in anatomical sciences. 562 MARY ANN BAKER AND JAMES N. HAYWARD sheep and undoubtedly affects hypothalamic thermoreceptors and temperature regulation in artiodactyls.