Effects of NMDA administration in the substantia nigra pars compacta on the striatal dopamine release before and after repetitive exposures to nitrogen narcosis in rats.
نویسندگان
چکیده
Hyperbaric nitrogen-oxygen exposure developed in rats a decrement of the striatal dopamine release, which was reversed by repetitive exposures. This dopamine decrease could be the result of the antagonistic effect of nitrogen on NMDA receptors. The increment of the dopamine release, following repetitive exposures to nitrogen, could be attributed to a desensitisation of NMDA receptors to the effects of nitrogen. To test these hypotheses, male Sprague-Dawley rats were implanted with electrodes in the striatum to measure dopamine release by voltammetry and cannula in the substantia nigra pars compacta for NMDA injection. Free-moving rats were exposed up to 3MPa of nitrogen-oxygen mixture before and after 5 exposures to 1MPa. At the first exposure to 3MPa, the dopamine level decreased (-15%) but is counteracted by NMDA administration. In contrast, after repetitive exposure, the second exposure to 3MPa, induces a 10% dopamine increase. NMDA administration significantly potentiated this increase. Our results neither support the hypothesis of an antagonist effect of nitrogen on NMDA receptors at the first exposure, nor that of a NMDA receptor desensitization following repetitive exposures to hyperbaric nitrogen.
منابع مشابه
A review of recent neurochemical data on inert gas narcosis.
Nitrogen narcosis occurs in humans at around 0.4 MPa (4 ATA). Hydrogen narcosis occurs between 2.6 and 3.0 MPa. In rats, nitrogen disturbances occur from 1 MPa and a loss of righting reflex around 4 MPa. Neurochemical studies in striatum of rats with nitrogen at 3 MPa (75% of anesthesia threshold) with differential pulse voltammetry have demonstrated a decrease in dopamine (DA) release by neuro...
متن کاملDopaminergic substantia nigra neurons express functional nmda receptors in postnatal rats.
Activation of N-methyl-D-aspartate (NMDA) receptors in the Substantia Nigra zona compacta (SNc) may determine the degree of physiological apoptosis during the early postnatal period. However, the expression of these receptors during this stage of development is uncertain, as a recent study failed to detect responses to NMDA in unidentified SNc neurons isolated from 2-wk-old rats. Using conventi...
متن کاملEndogenous dopamine can modulate inhibition of substantia nigra pars reticulata neurons elicited by GABA iontophoresis or striatal stimulation.
Previous reports from this laboratory have described an ability of iontophoretically applied dopamine to attenuate the inhibitory effects of iontophoresed GABA on neurons of the substantia nigra pars reticulata. This finding raised the question of whether endogenous dopamine, released from dendrites of neighboring pars compacta dopamine neurons, might act as a neuromodulator which diminishes th...
متن کاملThe effect of intrastriatal injection of estrogen on pallidal field potential and rigidity in Parkinsonian -ovariectomized rats
The major pathological feature of Parkinson’s disease (PD) is a progressive loss of dopamine-producing neurons of the substantia nigra pars compacta (SNc), resulting in a reduction of dopamine (DA) content in the target field of these neurons, the striatum (STR). The present evidences suggest that female sex hormones may influence the onset and severity of PD symptoms. PD is more prevalent in m...
متن کاملA study on striatal local electrical potential changes in an animal model of Parkinson's disease
Parkinson’s disease (PD) is a neurodegenerative disorder that does not develop spontaneously in some animal species. PD can be induced experimentally in some laboratory animals including mouse, rat and horse. Globus pallidus (GP) and substantia nigra pars compacta (SNc) are damaged in patients with PD. The hallmark of PD is a progressive impaired control of movement, an alteration of autonomic ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc
دوره 33 3 شماره
صفحات -
تاریخ انتشار 2006