Summary
We have established a totally-immersed, perfused slice preparation of the hypothalamus which is amenable for electrophysiological and pharmacological studies. The amount and pattern of spontaneous activity in the paraventricular nucleus (PVN) is markedly influenced by varying the amount of Ca++ in the oxygenated physiological medium which continuously perfuses the slice over both upper and lower surfaces. Ca++concentrations greater than 1 mM virtually abolish spontaneous activity, although the neurons discharge in response to advance of the electrode and are activated by addition of glutamate to the perfusate. However, in a perfusing medium containing 0.75 mM Ca++, most cells display 1–7 Hz spontaneous activity for up to 10 h; some cells display phasic activity similar to that attributed to vasopressin neurons in vivo. Electrical stimulation peripheral to the PVN elicits antidromic potentials in some PVN neurons, sometimes followed by a post-activation depression of activity typical of recurrent inhibition. Under appropriate perfusion conditions, therefore, the hypothalamic slice preparation displays characteristics of the in vivo hypothalamus.
Similar content being viewed by others
References
Ames A, Sakanoue M, Endo S (1964) Na, K, Ca, Mg and Cl concentrations in chloroid plexus fluid and cisternal fluid compared with plasma ultrafiltrate. J Neurophysiol 27: 672–681
Brimble MJ, Haller EW, Wakerley JB (1978) Supraoptic and paraventricular units in hypothalamic slices incubated in isoor hypertonic medium. J Physiol 278: 38–39p
Cross BA, Dyer RG (1971) Unit activity in rat diencephalic islands — the effect of anaesthetics. J Physiol 212: 467–481
Frankenhaeuser B, Hodgkin AL (1957) The action of calcium on the electrical properties of squid axons. J Physiol 137: 218–244
Haller EW, Brimble MJ, Wakerley JB (1978) Phasic discharge in supraoptic neurones recorded from hypothalamic slices. Exp Brain Res 33: 131–134
Harvey JA, McIlwain H (1969) Electrical phenomena and isolated tissues from the brain. In: Lajtha A (ed) Handbook of neurochemistry, vol II. Plenum Press, New York, pp 115–136
Hatton GI, Armstrong WE, Gregory WA (1978) Spontaneous and osmotically-stimulated activity in slices of rat hypothalamus. Brain Res Bull 3: 497–508
Hayward JN (1977) Functional and morphological aspects of hypothalamic neurons. Physiol Rev 57: 574–658
Heinemann U, Lux HD, Gutnick MJ (1977) Extracellular free calcium and potassium during paroxysmal activity in the cerebral cortex of the cat. Exp Brain Res 27: 237–243
Keesey JC, Wallgren H, McIlwain H (1965) The sodium, potassium and chloride of cerebral tissues: Maintenance, change on stimulation and subsequent recovery. Biochem J 95: 289–300
Koketsu K (1965) The role of calcium in membrane excitation. In: Proceedings of International Union of Physiology Sciences, vol IV. Tokyo, pp 521–541
Lolley RN (1963) The calcium content of isolated cerebral tissues and their steady-state exchange of calcium. J Neurochem 10: 665–676
Lynch G, Schubert P (1980) The use of in vitro brain slices for multidisciplinary studies of synaptic function. Ann Rev Neurosci 3: 1–22
Manery JF (1966) Effects of Ca ions on membranes. Fed Proc 25: 1804–1810
Nicholson C, ten Bruggencate G, Steinberg R, Stöckle H (1977) Calcium modulation in brain extracellular microenvironment demonstrated with ion-selective micropipette. Proc Natl Acad Sci USA 74: 1287–1290
Nicholson C, ten Bruggencate G, Stöckle H, Steinberg R (1978) Calcium and potassium changes in extracellular microenvironment of cat cerebellar cortex. J Neurophysiol 41: 1026–1039
Pittman QJ, Blume HW, Kearney RE, Renaud LP (1979) Influence of midbrain stimulation on the excitability of neurons in the medial hypothalamus of the rat. Brain Res 174: 39–53
Pittman QJ, Hatton JD, Bloom FE (1980) Morphine and opioid peptides reduce paraventricular neuronal activity: studies on the rat hypothalamic slice preparation. Proc Natl Acad Sci USA 77: 5527–5531
Poulain DA, Wakerley JB, Dyball REJ (1977) Electrophysiological differentiation of oxytocin- and vasopressin-secreting neurones. Proc R Soc Lond B 196: 367–384
Renaud LP, Blume HW, Pittman QJ (1978) Neurophysiology and neuropharmacology of the hypothalamic tuberoinfundibular system. In: Ganong WF, Martini L (eds) Frontiers in neuroendocrinology, vol. 5. Raven Press, New York, pp 135–162
Renaud LP, Pittman QJ, Blume HW (1979) Neurophysiology of hypothalamic peptidergic neurons. In: Fuxe K, Hokfelt T, Luft R (eds) Central regulation of the endocrine system. Plenum Press, New York, pp 119–136
Somjen GG, Kato G (1968) Effects of magnesium and calcium on neurones in the central nervous system. Brain Res 9: 161–164
Spencer HJ, Gribkoff VK, Cotman CW, Lynch GS (1976) GDEE antagonism of iontophoretic amino acid excitations in the intact hippocampus and in the hippocampal slice preparation. Brain Res 105: 471–481
Yamamoto C (1972) Activation of hippocampal neurons by mossy fiber stimulation in thin brain sections in vitro. Exp Brain Res 14: 423–435
Author information
Authors and Affiliations
Additional information
This work was supported by DA 01785
Supported by MRC of Canada
Rights and permissions
About this article
Cite this article
Pittman, Q.J., Hatton, J.D. & Bloom, F.E. Spontaneous activity in perfused hypothalamic slices: Dependence on calcium content of perfusate. Exp Brain Res 42, 49–52 (1981). https://doi.org/10.1007/BF00235728
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00235728