Sinteza i cAMP-ovisna inhibicija fosfodiesteraze novih derivata tiazolokinazolina

The series of 6,7,8,9-tetrahydro-5H-5-(2\u27-hydroxyphenyl)-2-(4\u27-substituted benzylidine) thiazolo(2,3-b)quinazolin-3(2H)-ones (4a-j) and 6,7,8,9-tetrahydro-5H-5-(2\u27-hydroxyphenyl)-2-(4\u27-substituted benzylidine)-3-(4-nitrophenylamino)thiazoloquinazolines (5a-j) were synthesized by the reported method and evaluated for their phosphodiesterase inhibitory activity. All test compounds exhibited good activity. The structure-activity relationships were also studied. In both series of compounds, electron-withdrawing substitutions showed higher activity. Among the tested compounds, 6,7,8,9-tetrahydro-5H-5-(2\u27-hydroxyphenyl)-2-(4\u27-fluorobenzylidine)-3-(4-nitrophenylamino)thiazoloquinazoline (5e), 6,7,8,9-tetrahydro-5H-5-(2\u27-hydroxyphenyl)-2-(4\u27-nitrobenzylidine)-3-(4-nitrophenylamino)thiazoloquinazoline (5j) and 6,7,8,9-tetrahydro-5H-5-(2\u27-hydroxyphenyl)-2-(4\u27-chlorobenzylidine)-3-(4-nitrophenylamino)thiazoloquinazoline (5f) were found to be more potent than theophylline (IC50 in mmol L–1 of 1.34 ± 0.09 for 5f, 1.44 ± 0.02 for 5e, 1.52 ± 0.05 for 5j vs. 1.72 ± 0.09 for theophylline).U radu je opisana sinteza serije 6,7,8,9-tetrahidro-5H-5-(2\u27-hidroksifenil)-2-(4\u27-supstituiranih benzilidin)tiazolo(2,3-b)kinazolin-3(2H)-ona (4a-j) i 6,7,8,9-tetrahidro-5H-5-(2\u27-hidroksifenil)-2-(4\u27-supstituiranih benzilidin)-3-(4-nitrofenilamino)tiazolokinazolina (5a-j) prema objavljenoj metodi te ispitano njihovo inhibitorno djelovanje na fosfodiesterazu. Svi testirani spojevi pokazuju dobro djelovanje. Proučavan je i odnos strukture i djelovanja. U obje serije spojeva, elektron-odvlačeći supstituenti doprinose jačem djelovanju. Među ispitivanim spojevima pronađeno je da 6,7,8,9-tetrahidro-5H-5-(2\u27-hidroksifenil)-2-(4\u27-fluorobenzilidine)-3-(4-nitrofenilamino)tiazolokinazolin (5e), 6,7,8,9-tetrahidro-5H-5-(2\u27-hidroksifenil)-2-(4\u27-nitrobenzilidine)-3-(4-nitrofenilamino)tiazolokinazolin (5j) i 6,7,8,9-tetrahidro-5H-5-(2\u27-hidroksifenil)-2-(4\u27-klorobenzilidin)-3-(4-nitrofenilamino)tiazolokinazolin (5f) imaju jače djelovanje od teofilina (IC50 u mmol L–1 1,34 ± 0,09 za 5f, 1,44 ± 0,02 za 5e, 1,52 ± 0,05 za 5j nasuprot 1,72 ± 0,09 za teofilin)

Network state-dependent inhibition of identified hippocampal CA3 axo-axonic cells in vivo.

Hippocampal sharp waves are population discharges initiated by an unknown mechanism in pyramidal cell networks of CA3. Axo-axonic cells (AACs) regulate action potential generation through GABAergic synapses on the axon initial segment. We found that CA3 AACs in anesthetized rats and AACs in freely moving rats stopped firing during sharp waves, when pyramidal cells fire most. AACs fired strongly and rhythmically around the peak of theta oscillations, when pyramidal cells fire at low probability. Distinguishing AACs from other parvalbumin-expressing interneurons by their lack of detectable SATB1 transcription factor immunoreactivity, we discovered a somatic GABAergic input originating from the medial septum that preferentially targets AACs. We recorded septo-hippocampal GABAergic cells that were activated during hippocampal sharp waves and projected to CA3. We hypothesize that inhibition of AACs, and the resulting subcellular redistribution of inhibition from the axon initial segment to other pyramidal cell domains, is a necessary condition for the emergence of sharp waves promoting memory consolidation

Behavior-dependent specialization of identified hippocampal interneurons.

A large variety of GABAergic interneurons control information processing in the hippocampal circuits governing the formation of neuronal representations. Whether distinct hippocampal interneuron types contribute differentially to information processing during behavior is not known. We employed a new technique for recording and labeling interneurons and pyramidal cells in drug-free, freely moving rats. Recorded parvalbumin-expressing basket interneurons innervated somata and proximal pyramidal cell dendrites, whereas nitric oxide synthase- and neuropeptide Y-expressing ivy cells provided synaptic and extrasynaptic dendritic modulation. Basket and ivy cells showed distinct spike-timing dynamics, firing at different rates and times during theta and ripple oscillations. Basket, but not ivy, cells changed their firing rates during movement, sleep and quiet wakefulness, suggesting that basket cells coordinate cell assemblies in a behavioral state-contingent manner, whereas persistently firing ivy cells might control network excitability and homeostasis. Different interneuron types provide GABA to specific subcellular domains at defined times and rates, thereby differentially controlling network activity during behavior

Behavior-dependent specialization of identified hippocampal interneurons.

A large variety of GABAergic interneurons control information processing in the hippocampal circuits governing the formation of neuronal representations. Whether distinct hippocampal interneuron types contribute differentially to information processing during behavior is not known. We employed a new technique for recording and labeling interneurons and pyramidal cells in drug-free, freely moving rats. Recorded parvalbumin-expressing basket interneurons innervated somata and proximal pyramidal cell dendrites, whereas nitric oxide synthase- and neuropeptide Y-expressing ivy cells provided synaptic and extrasynaptic dendritic modulation. Basket and ivy cells showed distinct spike-timing dynamics, firing at different rates and times during theta and ripple oscillations. Basket, but not ivy, cells changed their firing rates during movement, sleep and quiet wakefulness, suggesting that basket cells coordinate cell assemblies in a behavioral state-contingent manner, whereas persistently firing ivy cells might control network excitability and homeostasis. Different interneuron types provide GABA to specific subcellular domains at defined times and rates, thereby differentially controlling network activity during behavior