title: Changes in pre- and postsynaptic components of noradrenergic transmission in hippocampal kindling in rats.
abstract: We investigated whether modifications in noradrenergic neurotransmission occurred during the development of hippocampal kindling in rats. We measured the release of [3H]norepinephrine (NE) induced by field-electrical stimulation, NE-stimulation of inositol phosphates [( 3H]IP) accumulation in the presence of LiCl and isoproterenol-induced accumulation of cAMP in hippocampal slices taken from rats electrically kindled at stages 2 and 5 in the dorsal hippocampus. One week after the last of at least 3 consecutive stage 5 seizures or 48 h after the last stage 2 stimulation, 2 min electrical stimulation of stratum pyramidale CA1-CA3 or dentate gyrus (DG) slices from kindled and contralateral hippocampi induced frequency-dependent NE release (respectively 2, 4 and 8 times spontaneous release measured at 2, 5 and 10 Hz) which did not significantly differ from that observed in shams (implanted with electrodes but not stimulated). Basal release of NE from kindled and sham-treated rats did not differ either. Isoproterenol induced a dose-dependent increase above basal cAMP concentration ranging from 40% at 0.01 microM to 180% at 10 microM (P less than 0.01, Dunnett's test) which did not differ between stages 2 and 5 and sham-hippocampi. NE (1-1000 microM) induced a dose-dependent, prazosin-sensitive increase in [3H]IP accumulation in the hippocampal slices. A significantly higher increase was found at stages 2 (P less than 0.05, Tukey's test) and 5 (P less than 0.05 and P less than 0.01, Tukey's test) compared to shams at all doses studied.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Istituto di Ricerche Farmacologiche, Mario Negri, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Vezzani
authors.forename: M
authors.initials: M
authors.lastname: Rizzi
authors.forename: R
authors.initials: R
authors.lastname: Serafini
authors.forename: G
authors.initials: G
authors.lastname: Viganò
authors.forename: R
authors.initials: R
authors.lastname: Samanin
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004558:Electric Stimulation; D004569:Electroencephalography; D006624:Hippocampus / Q000166:cytology* / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D007696:Kindling, Neurologic / Q000502:physiology*; D008297:Male; D009638:Norepinephrine / Q000378:metabolism / Q000502:physiology*; D010716:Phosphatidylinositols / Q000378:metabolism; D011712:Pyramidal Tracts / Q000166:cytology / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D010716:Phosphatidylinositols; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D002217:Carbachol; D000242:Cyclic AMP; D007545:Isoproterenol; D009638:Norepinephrine