Publications (2)3.63 Total impact
Article: Noradrenaline-induced enhancement of oscillatory local field potentials in the mouse accessory olfactory bulb does not depend on disinhibition of mitral cells.[show abstract] [hide abstract]
ABSTRACT: The olfactory bulb differs from other brain regions by its use of bidirectional synaptic transmission at dendrodendritic reciprocal synapses. These reciprocal synapses provide tight coupling of inhibitory feedback from granule cell interneurons to mitral cell projection neurons in the accessory olfactory bulb (AOB), at the first stage of vomeronasal processing. It has been proposed that both the mGluR2 agonist DCG-IV and noradrenaline promote mate recognition memory formation by reducing GABAergic feedback on mitral cells. The resultant mitral cell disinhibition is thought to induce a long-lasting enhancement in the gain of inhibitory feedback from granule to mitral cells, which selectively gates the transmission of the learned chemosensory information. However, we found that local infusions of both noradrenaline and DCG-IV failed to disinhibit AOB neural activity in urethane-anaesthetised mice. DCG-IV infusion had similar effects to the GABA(A) agonist isoguvacine, suggesting that it increased GABAergic inhibition in the AOB rather than reducing it. Noradrenaline infusion into the AOB also failed to disinhibit mitral cells in awake mice despite inducing long-term increases in power of AOB local field potentials, similar to those observed following memory formation. These results suggest that mitral cell disinhibition is not essential for the neural changes in the AOB that underlie mate recognition memory formation in mice.European Journal of Neuroscience 04/2012; 35(9):1433-45. · 3.63 Impact Factor
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ABSTRACT: The effect of small and moderate doses of morphine (MF) on NK cell lytic activity (cytotoxicity, NKCC) (51Cr release test) and the number of circulating large granular lymphocytes (LGL) was evaluated in i.v. catheterized Pietrain crossbred pigs. Simultaneously, plasma cortisol (COR) (RIA method) was measured. Blood samples were collected 15, 60, 120, 180, and 240 min after i.v. injections of 0.5, 1.0 and 5.0 mg/kg of MF alone or MF pretreated with naloxone (NX, 1.0 mg/kg, i.v., 15 min before MF). It was found that MF induced dose- and time-dependent changes of NKCC. MF in a dose of 0.5 mg/kg evoked 4-fold increase in NKCC (in comparison to saline) without changes in the number of LGL/NK cells. Higher MF doses (1.0, 5.0 mg/kg) induced an early increase (up to 300Δ% and 29Δ%, respectively) followed by a decrease in cytotoxicity (to − 76Δ% after 5.0 mg/kg), and in LGL number (− 36Δ% after 5.0 mg/kg). These effects were concomitant with a marked rise in plasma COR (up to 234Δ% after 0.5 mg/kg and 567Δ% after 5.0 mg/kg of MF). NX pretreatment blocked all the changes in cytotoxicity but not in the LGL cell number and COR concentrations. The results indicate that MF, besides having well known immunosuppressive effects, can also enhance NKCC through the opioid receptors-dependent manner. The enhancement of cytotoxicity appears as a purely functional change independent of the recirculation of NK cells which occurs despite the high plasma concentrations of COR.International Immunopharmacology.