Journal of neurophysiology
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1. Within the hypothalamus, adenosine has been reported to influence temperature regulation, sleep homeostasis, and endocrine secretions. The effects of adenosine on hypothalamic neurons have not been studied at the cellular level. ⋯ In contrast to the modest effects found in neurons, responses of hypothalamic astrocytes to the application of glutamate or the metabotropic glutamate receptor agonist (+/-)-trans-1-amino-1,3-cyclopentanedicarboxylic acid were strongly potentiated by adenosine (mean +225%) and CPA. 9. Together, these findings suggest that adenosine exerts a major presynaptic effect and a minor postsynaptic effect in the modulation of glutamate neurotransmission in the hypothalamus, where it can play a significant role in blocking a large part of the glutamate-induced Ca2+ rise. In the absence of glutamate transmission, adenosine has relatively little effect on either neuronal intracellular Ca2+ or electrical activity.
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1. The properties of voltage-gated potassium currents were studied in acutely isolated rat hippocampal pyramidal cells from area CA1 and CA3 at postnatal ages of day 6-8, 9-14, and 26-29 (P6-8, P9-14, and P26-29) with the use of the whole cell version of the patch-clamp technique. 2. The outward current pattern of all cells under investigation could be separated in a fast transient A current (IA) and a delayed rectifier-like current (IK). 3. ⋯ This effect was more pronounced in CA3 than in CA1 cells. In contrast, IK was upregulated during the same developmental period. This increase in the expression of IK was with approximately 300% much larger in CA1 cells than in CA3 cells with only approximately 50%.
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1. The rostral ventromedial medulla (RVM) participates in the modulation of nociceptive transmission by spinal cord neurons. Previous anatomic studies have demonstrated that RVM neurons project to laminae I, II, and V of the dorsal horn; laminae VII and VIII of the intermediate and ventral horns; the intermediolateral column; and lamina X. ⋯ In general, all OFF cells and 9 of 10 ON cells were antidromically activated from low threshold points in either laminae I-II or lamina V. 6. In six cases, neurons were activated from separate points located in two or three different laminae of the gray matter. Three OFF cells were activated from laminae I-II and V, one OFF cell and one ON cell were activated from lamina V and from more ventral points, and one ON cell was activated from laminae I-II and from points ventral to lamina V.
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1. Injection of kaolin and carrageenan into the knee joint of cats or monkeys resulted in an acute inflammation. Four hours after injection of the knee joint, efferent activity could be evoked in articular afferent fibers and in dorsal root filaments. ⋯ The DRRs were again found in all fiber types, i.e., group II, III, and IV (A beta, A delta, and C) articular afferent fibers. 5. Compound DRRs were recorded from the central end of a cut dorsal root filament after electrical stimulation at C fiber intensity of a dorsal root adjacent to the filament. This DRR activity was eliminated by extensive dorsal rhizotomies of the L2-S1 roots.(ABSTRACT TRUNCATED AT 250 WORDS)
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1. Postnatal rat retinal ganglion cells (RGCs) can be maintained and identified in dissociated long-term culture. After 4-7 days in vitro they form glutamatergic synapses with other RGCs or putative amacrine cells. ⋯ Glutamate-activated currents were elicited by a rapid superfusion device (time constant of rise = 0.7 ms). The response to 1 mM of glutamate decayed 2 to 4 times more slowly than the sEPSCs. 7. These results suggest that desensitization did not limit the rate of decay of purely AMPA-mediated EPSCs in response to ganglion cell activation.(ABSTRACT TRUNCATED AT 400 WORDS)