Valentina Comunanza

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We studied the effects of the cAMP-hydrolyzing enzyme phosphodiesterase type-4 (PDE4) on the L-type Ca2+ channels (LTCCs) and Ca2+-dependent secretion in mouse chromaffin cells (MCCs). The selective PDE4 inhibitor rolipram (3 μM) had a specific potentiating action on Ca2+ currents of MCCs (40% increase within 3 min). A similar effect was produced by the(More)
Expression, spatial distribution and specific roles of different Ca2+ channels in stimulus–secretion coupling of chromaffin cells are intriguing issues still open to discussion. Most of the evidence supports a role of high-voltage activated (HVA) Ca2+ channels (L-, N-, P/Q- and R-types) in the control of exocytosis: some suggesting a preferential coupling(More)
Voltage-gated L-type (Cav1.2 and Cav1.3) channels are widely expressed in cardiovascular tissues and represent the critical drug-target for the treatment of several cardiovascular diseases. The two isoforms are also abundantly expressed in neuronal and neuroendocrine tissues. In the brain, Cav1.2 and Cav1.3 channels control synaptic plasticity, somatic(More)
alpha(1H) T-type channels recruited by beta(1)-adrenergic stimulation in rat chromaffin cells (RCCs) are coupled to fast exocytosis with the same Ca(2+) dependence of high-threshold Ca(2+) channels. Here we show that RCCs exposed to chronic hypoxia (CH) for 12-18 h in 3% O(2) express comparable densities of functional T-type channels that depolarize the(More)
Voltage-gated Ca2+ channels (Cav) are highly expressed in the adrenal chromaffin cells of mammalian species. Besides shaping action potential waveforms, they are directly involved in the excitation-secretion coupling underlying catecholamine release and, possibly, control other Ca2+-dependent events that originate near the membrane. These functions are(More)
BACKGROUND AIMS Amniotic fluid (AF) contains stem cells with high proliferative and differentiative potential that might be an attractive source of multipotent stem cells. We investigated whether human AF contains mesenchymal stem cells (MSC) and evaluated their phenotypic characteristics and differentiation potential in vitro. METHODS AF was harvested(More)
We studied the inhibitory effects of transient receptor potential vanilloid-1 (TRPV1) activation by capsaicin on low-voltage-activated (LVA, T-type) Ca2+ channel and high-voltage-activated (HVA; L, N, P/Q, R) currents in rat DRG sensory neurons, as a potential mechanism underlying capsaicin-induced analgesia. T-type and HVA currents were elicited in(More)
Voltage-gated L-type calcium channels (LTCCs) are expressed in adrenal chromaffin cells. Besides shaping the action potential (AP), LTCCs are involved in the excitation-secretion coupling controlling catecholamine release and in Ca (2+) -dependent vesicle retrieval. Of the two LTCCs expressed in chromaffin cells (CaV1.2 and CaV1.3), CaV1.3 possesses the(More)
Carcinomas are comprised of transformed epithelial cells that are supported in their growth by a dedicated neovasculature. How the genetic milieu of the epithelial compartment influences tumor angiogenesis is largely unexplored. Drugs targeted to mutant cancer genes may act not only on tumor cells but also, directly or indirectly, on the surrounding stroma.(More)
Using immortalized hypothalamic GT1-7 neurons, which express the CB1 cannabinoid receptor (CB1R) and three Ca2+ channel types (T, R and L), we found that the CB1R agonist WIN 55,212-2 inhibited the voltage-gated Ca2+ currents by about 35%. The inhibition by WIN 55,212-2 (10 microM) was reversible and prevented by nifedipine (3 microM), suggesting a(More)