Wandikayi C Matowe

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The major projection cells of the nucleus accumbens (NAc) are under a strong inhibitory influence from GABAergic afferents and depend on afferent excitation to produce their output. We have earlier reported that substance P (SP), a peptide which is colocalized with GABA in these neurons, depresses excitatory synaptic transmission in this nucleus (Kombian,(More)
The peptide cholecystokinin (CCK) is abundant in the rat nucleus accumbens (NAc). Although it is colocalized with dopamine (DA) in afferent terminals in this region, neurochemical and behavioural reports are equally divided as to whether CCK enhances or diminishes DA's actions in this nucleus. To better understand the role of this peptide in the physiology(More)
Substance P (SP) is an undecapeptide that is co-localized with conventional transmitters in the nucleus accumbens (NAc). Its neurochemical and behavioral effects resemble those of cocaine and amphetamine. How SP accomplishes these effects is not known, partly because its cellular and synaptic effects are not well characterized. Using whole cell and(More)
OBJECTIVES This study set out to determine the roles of protein kinase A (PKA) and protein kinase C (PKC) signalling cascades in substance P- (SP-) mediated synaptic depression in the nucleus accumbens. MATERIALS AND METHODS We used whole-cell patch recording in rat forebrain slices to study the effects of excitatory and inhibitory modulators of PKA and(More)
Protein kinase C (PKC) is involved in the alpha1-adrenergic-potentiation of beta-adrenergic stimulated cyclic nucleotide responses in rat pinealocytes. In the present study, the PKC isozymes expressed in rat pinealocytes and their regulation by norepinephrine (NE) were investigated. Western blot analysis identified PKC alpha (a classical PKC isozyme), PKC(More)
We recently reported that the activation of cholecystokinin-2 receptors depress evoked excitatory postsynaptic currents (EPSCs) in nucleus accumbens (NAc) indirectly through gamma-aminobutyric acid (GABA) acting on gamma-aminobutyric acid-B (GABA(B)) receptors. Here, we determined the second messenger system that couples cholecystokinin-2 receptors to the(More)
We recently reported that cholecystokinin (CCK) excited nucleus accumbens (NAc) cells and depressed excitatory synaptic transmission indirectly through gamma-aminobutyric acid (GABA), acting on presynaptic GABAB receptors (Kombian et al. [2004] J. Physiol. 555:71-84). The present study tested the hypothesis that CCK modulates inhibitory synaptic(More)
High-frequency stimulation of afferents to the supraoptic nucleus (SON) results in a robust increase in the frequency and amplitude of pharmacologically isolated, tetrodotoxin-resistant, miniature excitatory postsynaptic currents (mEPSCs) lasting for 5-20 min. This increase in mEPSC frequency, termed short-term potentiation (STP), is tightly coupled to(More)
We have previously shown that the abilities of the two native goldfish GnRHs, salmon GnRH (sGnRH) and chicken GnRH II (cGnRH II), to stimulate gonadotropin (GtH) secretion and elevate intracellular Ca2+ levels are mimicked by the protein kinase C (PKC) stimulators, 1,2-dioctanoylglycerol (DiC8) and 12-O-tetradecanoyl phorbol-13-acetate (TPA). The ability of(More)
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