Spike-timing-dependent synaptic plasticity (STDP) by definition requires the temporal association of pre- and postsynaptic action potentials (APs). Yet, in cortical pyramidal neurons pairing unitary EPSPs with single APs at low frequencies is ineffective at generating plasticity. Using recordings from synaptically coupled layer 5 pyramidal neurons, we show here that high-frequency (200 Hz) post...

Objective(s) Four novel losartan analogues 5a-d were synthesized by connecting a dihydropyridine nucleus to imidazole ring. The effects of 5a and 5b on angiotensin receptors (AT') and L-type calcium channels were investigated on isolated rat aorta. Materials and Methods Aortic rings were pre-contracted with 1 pM Angiotensin II or 80 mM KCl and relaxant effects of losartan, nifedipine, 5a and...

objective(s) calcium-channel blockers have an important role in the treatment of several cardiovascular disorders. derivatives of 1, 4-dihydropyridine are one of the most potent calcium antagonists. in this study four novel ', 4-dihydropyridine calcium channel blockers were synthesized and their hypotensive properties were investigated in male rats. materials and methods four 1, 4-dihydrop...

in order to investigate the effects of dimethylamino substituent at postion 2 of the dihydropyridine nucleus on its activity, dialkyl 1,4-dihydro-2-[2-(dimethy- lamino) ethyl]-6-methyl-4-(1-benzyl-2-alkylthio-5-imidazolyl)-3,5-pyrdinedicar- boxylates (6a-f) were synthesized. the synthesis was started from dialkyl 1,4- dihydro-2,6-dimethyl-4-(1-benzyl-2-alkylthio-5-imidazolyl)-3,5-pyridinedicar-...

background calcium infusion is used as a pre-treatment before calcium channel blockers to prevent hypotension. occasional cardioversion with calcium gluconate infusion is seen in patients with paroxysmal supraventricular tachycardia. several mechanisms have been suggested for mechanism. herein we report a case presenting with atrial fibrillation but cardioverted with calcium gluconate infusion,...

The functional activity of hippocampal neurons is strongly correlated with behavioral performance in a vertebrate model learning system, rabbit eyeblink conditioning. Using this system, we have previously shown that (a) complete removal of the hippocampus blocks acquisition of the conditioned response; (b) a calcium-dependent postsynaptic afterhyperpolarization is reduced in pyramidal cells rec...

Depletion of intracellular calcium stores by agonist stimulation is coupled to calcium influx across the plasma membrane, a process termed capacitative calcium entry. Capacitative calcium entry was examined in cultured guinea pig enteric glial cells exposed to endothelin 3. Endothelin 3 (10 nM) caused mobilization of intracellular calcium stores followed by influx of extracellular calcium. This...

Flunarizine, a calcium channel antagonist of the piperazine class, has been labeled with the positron-emitter 18F.4-[18F]Fluoro-4-fluorobenzhydryl chloride was prepared in three steps from no-carrier-added [18F]fluoride ion, and used in the alkylation of N-cinnamylpiperazine to give [18F]flunarizine in 13% radiochemical yield (from [18F]fluoride).