Biomaterial Database

Dorsal hippocampus field CA1 pyramidal cell responses to a persistent versus an acute nociceptive stimulus and their septal modulation. 1997

S Khanna

Department of Physiology, The National University of Singapore.

In urethane anaesthetized rats subcutaneous formalin injection in the right hind paw, a model of persistent pain, produced (i) a prolonged increase in the period of field rhythmic sinusoidal (or theta) activity, (ii) a depression of dorsal hippocampal field CA1 pyramidal cell synaptic excitability (mean peak depression of population spike amplitude being 50 +/- 6%) observed to the 60th min post injection, and (iii) a persistent decrease in extracellular activity of the majority of CA1 pyramidal cells (15/20 or 75%) with only a small percentage excited (5/20 or 25%). In contrast an intense noxious heat stimulus applied briefly to the distal end of the tail evoked a short duration increase in period of theta activation and suppression of pyramidal cell responses. With this acute stimulus the proportion of CA1 pyramidal cells excited (8/16) were similar to that suppressed (7/16). Finally, electrolytic lesions centred in the medial septal vertical limb of diagonal band of Broca (or septal region) prevented a noxious stimulus-induced theta and depression of CA1 pyramidal cell responses. Rather, in such lesioned animals noxious stimulation excited the majority CA1 complex spike cells studied (8/10). The above data are consistent with the notion that septohippocampal inputs are involved in noxious stimulus-induced CA1 pyramidal cell suppression. The formalin injection-induced selective activation of CA1 complex spike cells against a background of widespread pyramidal cell suppression might produce a "signal to noise" contributory to nociceptive processing in limbic structures. Such a processing might be involved in the affective motivational component of pain.

UI	MeSH Term	Description	Entries
D007839	Functional Laterality	Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.	Ambidexterity,Behavioral Laterality,Handedness,Laterality of Motor Control,Mirror Writing,Laterality, Behavioral,Laterality, Functional,Mirror Writings,Motor Control Laterality,Writing, Mirror,Writings, Mirror
D008297	Male		Males
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D009991	Oscillometry	The measurement of frequency or oscillation changes.	Oscillometries
D010146	Pain	An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.	Suffering, Physical,Ache,Pain, Burning,Pain, Crushing,Pain, Migratory,Pain, Radiating,Pain, Splitting,Aches,Burning Pain,Burning Pains,Crushing Pain,Crushing Pains,Migratory Pain,Migratory Pains,Pains, Burning,Pains, Crushing,Pains, Migratory,Pains, Radiating,Pains, Splitting,Physical Suffering,Physical Sufferings,Radiating Pain,Radiating Pains,Splitting Pain,Splitting Pains,Sufferings, Physical
D001931	Brain Mapping	Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.	Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D004569	Electroencephalography	Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.	EEG,Electroencephalogram,Electroencephalograms
D005557	Formaldehyde	A highly reactive aldehyde gas formed by oxidation or incomplete combustion of hydrocarbons. In solution, it has a wide range of uses: in the manufacture of resins and textiles, as a disinfectant, and as a laboratory fixative or preservative. Formaldehyde solution (formalin) is considered a hazardous compound, and its vapor toxic. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p717)	Formalin,Formol,Methanal,Oxomethane
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D006614	Hindlimb	Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)	Hindlimbs