Effects Of Nicotine On Sensory Stinulation-evolced Responses In The Field Potential In The Cerebellar Granule Cell Layer In Vivo In Mice

Aim:N-type acetylcholine receptor(nAChRs)exists in the mammalian cerebellar cortical nerve loop,and nicotine can activate nAChRs to affect the activity of various neurons in the cerebellar cortex by regulating other receptors and transmitters,but the effect of nicotine on the sensory information transmission of the granular cell layer of the cerebellar layer of mammalian cerebellum is not clear.Therefore,the effect of different doses of nicotine on the field potential activity of cerebellar granular cell layer induced by sensory stimulation and the mechanism of nicotine on the sensory information transmission of granular layer in the cerebellar cortex will be investigated in vivo.Methods:Kunming mice were anaesthetized by intraperitoneal injection of urethane,and after intubation,the mice were fixed on a self-made in-vivo record holder using ear sticks and mouth fixators.Then,the scalp skin and muscle tissue of the part to be recorded are removed,the skull is exposed to the air,a perfusion chamber is placed at the recording site,and craniotomy is performed.The skull was removed with a dental drill,the dura mater was stripped,and superficial perfusion was performed with oxygenated artificial cerebrospinal fluid at the recording site.The cerebellar granule cell field potential was recorded by an Axopatch-200B amplifier,and the extracellular recording of the granular cell layer was approximately 300-400μm below the pia mater.The recorded data was recorded on a computer using Clampex 10.3 software using a 1440 D/A converter.The recording glass electrode was drawn by a pulling device,and about 20-30 μL of ACSF was filled in the recording glass electrode.The hair sensation irritation ipsilateral whisker pad is a 12-gauge steel tube connected to a gas-jet device for air stimulation(time course 5-500 ms,pressure 50-60 psi).Picospritzer performs simultaneous electrophysiological recordings using the Marster 8 controller(AMPI)and Clampex 10.3 software.Using a recording electrode to record the field potential induced by sensory stimuli with a patch clamp amplifier,use a microscope to look for the recorded portion of the cerebellum,place the recording glass electrode in the recording portion,and use the micromanipulator to carefully pierce the recording electrode under the pia mater to reach the cerebellum After the cortical granule cell layer was given a hairy sensation stimulus,the maximal response recording site was searched,and the field potential was recorded.The peristaltic pump was used to perfuse nicotine and its receptor blocker on the surface of the cerebellar cortex to observe the change in the field potential due to the drug.Electrophysiological data were analyzed using Clampfit 10.4 software.The experimental data were expressed as mean±standard error.The differences were assessed using standard paired t-test or analysis of variance using SPSS analysis software.When P<0.05,it was considered that there was a statistically significant difference between the experimental groups.Results:(1)In the current clamp recording mode,facial hair stimuli(60 ms,60 psi)can induce excitatory responses in the granule cell layer of the cerebellar cortex,and amplitudes and waveforms of N1,N2 after perfusion of Nicotine(0.5 mM)on the brain surface Larger than before perfusion,suggesting that the excitatory response of cerebellar granule cell layer is enhanced.(2)The increase in amplitude caused by air-shock stimulation after perfusion of Nicotine(0.5 mM)on the brain surface is dose-dependent and can increase the amplitude of field-potential-initiated response of mouse granule cells induced by sensory stimulation in a dose-dependent manner,according to the concentration-response curve.The median effective concentration(EC50)was 398μM.(3)Nicotine increased sensory stimuli induced cerebellar cortical particle layer response N1,N2 amplitude and area under the waveform,and the ratio of N2/N1,indicating that nicotine affects sensory stimuli induced switch response and sensory information transmitted in the granular layer of high security True characteristics.(4)Nitric oxide had no significant effect on the amplitude and AUC of the field-potential response of granule cell layer induced by sensory stimulation after perfusing brain hexamethylenediamine on the brain surface.There was no significant difference from pre-dose,indicating that nicotine enhances sensory stimulation through nAChRs.Induced field potential response intensity of mouse granule cell layer.(5)Nicotine increased the amplitude and waveform area of N1 and N2 in the cerebellar cortex of mice induced by sensory stimulation by activating presynaptic nAChRs,and the ratio of N2/N1.Conclusion:Nicotine induces sensory stimulation to induce the enhancement of the field potential response in the granular cell layer of the cerebellar cortex of mice via activation of nAChRs,which affects the high fidelity of sensory information transmission in the granular cell layer,suggesting that the nAChRs system is involved in the transmission and integration of the sensory information of the granular layer of the cerebellar cortex of mammals.