scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Osmosensitive single neurones in the hypothalamus of unanaesthetized monkeys.

01 Nov 1970-The Journal of Physiology (Wiley-Blackwell)-Vol. 210, Iss: 4, pp 947-972
TL;DR: This work recorded with tungsten micro‐electrodes the activity of single neurones in the supraoptic nucleus (NSO) and adjacent regions of the hypothalamus while repeatedly injecting solutions of varying tonicity into the common carotid artery of trained, unanaesthetized monkeys who accepted the experimental restraints without anxiety.
Abstract: 1. We recorded with tungsten micro-electrodes the activity of single neurones in the supraoptic nucleus (NSO) and adjacent regions of the hypothalamus while repeatedly injecting solutions of varying tonicity into the common carotid artery of trained, unanaesthetized monkeys who accepted the experimental restraints without anxiety. 2. Intracarotid injections of mildly hypertonic solutions of sodium chloride produced a characteristic behavioural response during and immediately after injection: e.e.g. ‘arousal,’ lip and tongue smacking, chewing, irregular sniffing respiration and associated mildly increased movement of face, eyes and body. 3. Of the 130 cells analysed during hypertonic intracarotid injections, 105 (81%) were osmosensitive. Twenty-five (19%) of the cells studied during similar injections were non-osmosensitive. On the basis of the anatomical location of the cells, the pattern of discharge to intracarotid osmotic stimuli and the response to arousing sensory stimuli, we divided the osmosensitive cells into two major groups, ‘specific’ and ‘non-specific’ osmosensitive cells. 4. Fifty-two (50%) of the osmosensitive cells we labelled ‘specific’ because they responded to an intracarotid injection of hypertonic sodium chloride, generally did not respond to non-noxious arousing sensory stimuli and were located in or near the supraoptic nucleus. We found two subtypes of these ‘specific’ osmosensitive cells: (a) twenty-one (20%) NSO cells with ‘biphasic’ responses, that is, acceleration followed by inhibition; (b) thirty-one (30%) cells in the immediate perinuclear zone of the NSO with ‘monophasic’ responses, subdivided into twenty-one (20%) cells that accelerated and ten (10%) that were inhibited. 5. Fifty-three osmosensitive cells (50%), located diffusely in the anterolateral hypothalamus, were ‘non-specific’, responding both to intracarotid injections of hypertonic sodium chloride and also to sensory stimuli that were mildly arousing. Two groups of ‘non-specific’ osmosensitive cells showed monophasic responses; thirty-five (34%) cells accelerated and seventeen (16%) of them were inhibited. 6. The ‘monophasic’ specific osmosensitive neurones lying in the immediate perinuclear zone of the supraoptic nucleus in the primate could conceivably be the ‘osmoreceptors’ of Verney. The ‘biphasic’ specific osmosensitive neurones in the NSO may well represent the secretory cells of this system. From our data, the ‘non-specific’ osmosensitive neurones, scattered diffusely in the anterolateral hypothalamus, have little to do with osmoregulation. Some of these cells located in the perinuclear zone of the NSO could act as interneurones, however, conveying afferent input to the osmoreceptor-secretory complex of the supraoptic nucleus.
Citations
More filters
Journal ArticleDOI
TL;DR: The hypothesis that nerve cells are true secreting cells, and act upon one other and upon the cells of other organs by the passage of a chemical substance of the nature of a ferment or proferment from the first cell to the second is formed.

806 citations

Book ChapterDOI
TL;DR: The osmoregulation of AVP can be readily understood by analyzing the relationship between plasma AVP and plasma osmolality under different conditions of water balance.
Abstract: Publisher Summary This chapter describes anti-diuretic hormone arginine vasopressin (AVP), lysine vasopressin (EVP), urinary AVP, plasma AVP-osmolality, and the chromatographic behavior of purified bovine AVP on Sephadex G-15 with different eluting solvents or sample composition. As immunoassay methods can be used successfully to develop simple and accurate assays, plasma AVP has re-stimulated much investigative interest and, as a consequence, many other laboratories are beginning to develop their own assay procedures. It has been known for almost 30 years that the secretion of AVP can be influenced by a number of factors, including changes in blood osmolality, volume, and pressure. However, the relative potency of these variables and the way in which they interact in regulating secretion of the hormone under different conditions of salt and water balance has been a subject of some dispute. The advent of the immunoassay technique has now made it possible to begin to define these aspects of AVP physiology in more precise and comprehensive terms. The osmoregulation of AVP can be readily understood by analyzing the relationship between plasma AVP and plasma osmolality under different conditions of water balance.

361 citations

Journal ArticleDOI
TL;DR: It is suggested that the rate of vasopressin secretion into the circulation largely depends on the proportion of vasipressin neurones firing phasically, their firing rates within the phases and the duration and degree of synchronization of the phases.
Abstract: Antidromically identified neurosecretory cells of the paraventricular (p.v.) and supraoptic (s.o.) nuclei of the hypothalamus were recorded in lactating rats under urethane anaesthesia during reflex milk ejection (m.e.) and haemorrhage. Eighty one p.v. and s.o. neurones were studied. Their background firing rates ranged from < 0.1 to 6.3 spikes/s and three distinct patterns of activity were encountered: slow irregular (73%), fast continuous (10%) and phasic (17%). Forty units (49%) displayed a brief (2-4 s) high-frequency discharge (30-60 spikes/s) correlated with suckling-induced m.e., and these were classified as m.e. (oxytocin-secreting) neurones. The remainder of the cells showed no activation at this time and were classified as non-m.e. neurones. Ten m.e. neurones tested through haemorrhage (5 ml of blood) showed a gradual acceleration of firing rates, reaching a maximum of 3.7 $\pm $ 0.7 spikes/s (mean $\pm $ s.e.) about 20 min after blood withdrawal. The firing pattern of the m.e. neurones therefore changed from a slow irregular to a fast continuous type. By contrast, 11 non-m.e. neurones tested with the same procedure showed a rapid activation reaching a maximum of 6.4 $\pm $ 0.6 spikes/s by the fourth minute. Non-m.e. neurones which were initially of the slow irregular type, first became fast continuous and later evolved into a highly characteristic phasic pattern of activity which was never induced in the m.e. neurones. After the blood was replaced, all the cells returned to their original firing pattern. In a parallel series of experiments, plasma samples taken 5 and 25 min after haemorrhage showed a ten-fold elevation in antidiuretic activity. A slight but non-significant increase in m.e. activity was also observed. Thus p.v. and s.o. neurosecretory cells may be electrophysically differentiated into two functionally distinct populations: (1) oxytocin releasing neurones which show a high-frequency discharge before m.e. induced by suckling, and (2) vasopressin-releasing neurones which adopt a phasic pattern of firing during vasopressin release induced by haemorrhage. We suggest that the rate of vasopressin secretion into the circulation largely depends on the proportion of vasopressin neurones firing phasically, their firing rates within the phases and the duration and degree of synchronization of the phases.

224 citations

Journal ArticleDOI
TL;DR: Both vasopressin and oxytocin neurones are activated during chronic dehydration, but there is a marked difference in the pattern of their response, which is important in increasing the occurrence of short interspike intervals and thus facilitating hormone release.

221 citations

Journal ArticleDOI
TL;DR: The firing patterns of activated OT and VP neurons often differ, but can transiently appear indistinguishable in vivo and especially in vitro, and classification in vitro without immunochemical labelling may be aided by the presence of phasic bursting and by the differential response of these neurons to certain neurochemicals or to stimulation of certain inputs.

221 citations

References
More filters
Journal ArticleDOI
TL;DR: The statistical techniques available for the analysis of single spike trains are described and related to the underlying mathematical theory, that of stochastic point processes, whose realizations may be described as series of point events occurring in time, separated by random intervals.

1,452 citations

Journal ArticleDOI
TL;DR: The technique allows stereotaxic orientation of micro-electrodes for single unit recording in the intact monkey and provides for vertical penetrations and for minimum loss of time between completion of one penetration and reorientation of the electrode for the subsequent penetration.

264 citations

Journal ArticleDOI
TL;DR: The concept of the role of the cerebral arterial blood in homeothermy of the brain in the primate is applicable as a general approach to the study of brain temperature and temperature regulation in other mammals.
Abstract: HAYWARD,JAMESN., AND MARY ANN BAKER. Role of cmdral arterial blood in the rqphtion of brain temperature in the monkey. Am. J. Physiol. 215(Z): 389-403. 1.968.-The major determinant of cerebral temperatures in the monkey is the temperature of the arterial blood perfusing the brain. We measured arterial blood temperatures in the aortic arch simultaneously with those at extracranial and intracranial sites in 16 chronic monkeys. Sequential thermal changes occurred in the central arterial blood, cerebral. arterial blood, and in the brain during feeding, sleeping, arousal, and saline injections. Information about the thermal state of the body core is carried rapidly by the arterial blood to the thermodetector neural elements in the preoptic-anterior hypothalamic region of the brain. Maneuvers which after ventilation and the levels of carbon dioxide in the blood c.ln change the tone of the cerebral vessels and cause a shift in cerebral blood flow. In our monkeys such shifts in the rate of AO~V of the cooler arterial blood through the j(varmer brain altered the convective heat transfer in the brain and predictably changed the brain-blood temperature gradients. Our concept of the role of the cerebral arterial blood in homeothermy of the brain in the primate is applicable as a general approach to the study of brain temperature and temperature regulation in other mammals.

244 citations