A role for L-type calcium channels in developmental regulation of transmitter phenotype in primary sensory neurons.
نویسندگان
چکیده
To examine the influence of activity-dependent cues on differentiation of primary afferent neurons, we investigated the short- and long-term effects of depolarization and calcium influx on expression of transmitter traits in sensory ganglion cell cultures. We focused on expression of tyrosine hydroxylase (TH), a marker for dopaminergic neurons, in developing petrosal ganglion (PG), nodose ganglion, and dorsal root ganglion neurons grown in the presence or absence of depolarizing concentrations of KCl. Exposure to 40 mM KCl increased the proportion of TH-immunoreactive neurons in all three ganglia in a developmentally regulated manner that corresponded to the temporal pattern of dopaminergic expression in vivo. PG neurons, for example, were most responsive to elevated KCl on embryonic day 16.5 (E16.5), the age at which the dopaminergic phenotype is first detectable in vivo. However, KCl was relatively ineffective at increasing TH expression in neonatal PG, indicating a critical period for induction of this phenotype by depolarization. Detailed analysis of TH induction in PG neurons demonstrated that, although N-type calcium channels carried the majority of the high voltage-activated calcium current, only L-type calcium channel blockade inhibited the effect of elevated KCl. Further studies revealed that after removal of high KCl, neurons remained sensitized to subsequent stimulation for >1 week. Specifically, cultures exposed to KCl beginning on E16.5 (the conditioning stimulus), then returned to control medium, and subsequently re-exposed to elevated KCl after 9 d (the test stimulus) contained fourfold more TH-positive neurons than did cultures exposed to the test stimulus alone. Moreover, blockade of L-type calcium channels during the conditioning stimulus completely abolished long-term potentiation of the TH response to elevated KCl. These findings demonstrate a novel role for L-type calcium channels in activity-dependent plasticity of transmitter expression in sensory neurons and indicate that exposure to depolarizing stimuli during early development may alter neuronal response properties at later ages.
منابع مشابه
Involvement of voltage-dependent calcium channels in synaptic plasticity of the rat visual cortex
In this study, involvement ofvoltage-dependent calcium channels in LTP of responses of rat visual cortex slices was analyzed. Field potentials including EPSP1 and EPSP2 from layers II/III were recorded through stimulation of layer IV. Whereas nifedipine, a L-type calcium channel blocker (L-VDCC), did not considerably affect the LTP of responses, but Ni2+, a relatively selective blocker of T-typ...
متن کاملInvolvement of voltage-dependent calcium channels in synaptic plasticity of the rat visual cortex
In this study, involvement ofvoltage-dependent calcium channels in LTP of responses of rat visual cortex slices was analyzed. Field potentials including EPSP1 and EPSP2 from layers II/III were recorded through stimulation of layer IV. Whereas nifedipine, a L-type calcium channel blocker (L-VDCC), did not considerably affect the LTP of responses, but Ni2+, a relatively selective blocker of T-typ...
متن کاملInhibition of olfactory receptor neuron input to olfactory bulb glomeruli mediated by suppression of presynaptic calcium influx Abbreviated title: Presynaptic inhibition of olfactory receptor neurons
We investigated the cellular mechanism underlying presynaptic regulation of olfactory receptor neuron (ORN) input to the mouse olfactory bulb using optical imaging techniques that selectively report activity in the ORN presynaptic terminal. First, we loaded ORNs with calcium-sensitive dye and imaged stimulus-evoked calcium influx in a slice preparation. Single olfactory nerve shocks evoked rapi...
متن کاملRole of a voltage-sensitive calcium channel blocker on inhibition of apoptosis in sensory neurons of cultured dorsal root ganglia in adult rat
Introduction: Under pathological conditions, abnormal increase in intracellular calcium concentrations is believed to induce cell death. In the present study, a voltage-sensitive calcium channel blocker (loperamide hydrochloride) was used to investigate its role in inhibition of apoptosis in sensory neurons of cultured spinal dorsal root ganglia (DRG). Methods: L5 DRG from adult rats were di...
متن کاملTyrosine hydroxylase expression in primary cultures of olfactory bulb: role of L-type calcium channels.
Sensory activity mediates regulation of tyrosine hydroxylase (TH), the first enzyme in the dopamine biosynthetic pathway, in the rodent olfactory bulb. The current studies established for the first time primary cultures of neonatal mouse olfactory bulb expressing TH and tested whether L-type calcium channels mediate the activity-dependent regulation of the dopamine phenotype. After 1 d in vitro...
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:
- The Journal of neuroscience : the official journal of the Society for Neuroscience
دوره 18 3 شماره
صفحات -
تاریخ انتشار 1998