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Neural circuits containing olfactory neurons are involved in the prepulse inhibition of the startle reflex in rats.

Niu H, He X, Zhou T, Shi X, Zhang Q, Zhang Z, Qiao Y, Xu F, Hu M - Front Behav Neurosci (2015)

Bottom Line: Our results demonstrated that blockage of olfactory sensory input could disturb olfactory behavior.In the function studies, we demonstrated that blockage of olfactory sensory input could impair the pre-pulse inhibition of the startle response following decreased c-Fos expression in relevant brain regions during the PPI responses.Thus, these data suggest that the olfactory system participates in the PPI regulating fields and plays a role in the pre-pulse inhibition of the startle response in rats.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Xuzhou Medical College Xuzhou, China ; The Institute of Audiology and Speech Science, Xuzhou Medical Collage Xuzhou, China.

ABSTRACT
Many neuropsychiatric disorders, such as schizophrenia, have been associated with olfactory dysfunction and abnormalities in the prepulse inhibition (PPI) response to a startle reflex. However, whether these two abnormalities could be related is unclear. The present investigations were designed to determine whether theblockage of olfactory sensory input by zinc sulfate infusion in the olfactory naris (0.5 ml, 0.17 M, ZnE) can disturb the PPI response. Furthermore, a bilateral microinjection of lidocaine/MK801 in the olfactory bulb (OB) was administered to examine whether the blockage of olfactory sensory input could impair the PPI response. To identify the neural projection between olfaction and PPI-related areas, trans-synaptic retrograde tracing with the recombinant pseudorabies virus (PRV) was used. Our results demonstrated that blockage of olfactory sensory input could disturb olfactory behavior. In the function studies, we demonstrated that blockage of olfactory sensory input could impair the pre-pulse inhibition of the startle response following decreased c-Fos expression in relevant brain regions during the PPI responses. Furthermore, similar and more robust findings indicated that blockage of olfactory sensory input by microinjection of lidocaine/MK801 in the OB could impair the PPI response. In the circuit-level studies, we demonstrated that trans-synaptic retrograde tracing with PRV exhibited a large portion of labeled neurons in several regions of the olfactory cortices from the pedunculopontine tegmental nucleus (PPTg). Thus, these data suggest that the olfactory system participates in the PPI regulating fields and plays a role in the pre-pulse inhibition of the startle response in rats.

No MeSH data available.


Related in: MedlinePlus

The effect of lidocaine or MK801 bilateral microinjections into the OB on the ASR and PPI. (A) Acoustic startle amplitude of the rats administered bilateral microinjections of lidocaine or MK801 in the OB. A one-way ANOVA indicated there was no significant difference between the groups. (B) The PPI (%) of the rats with the OB inhibited with lidocaine or MK801 at three different auditory prepulse intensities (70, 75 and 80 dB). A repeated measures ANOVA of the prepulse data identified significant effects of drug treatment (F(3,20) = 5.74, p < 0.05). The values indicate the mean ± SD (n = 6). * indicates a significant difference compared with the vehicle group (p < 0.05). (C) A representative photograph of the OB that indicates the microinjection site.
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Figure 3: The effect of lidocaine or MK801 bilateral microinjections into the OB on the ASR and PPI. (A) Acoustic startle amplitude of the rats administered bilateral microinjections of lidocaine or MK801 in the OB. A one-way ANOVA indicated there was no significant difference between the groups. (B) The PPI (%) of the rats with the OB inhibited with lidocaine or MK801 at three different auditory prepulse intensities (70, 75 and 80 dB). A repeated measures ANOVA of the prepulse data identified significant effects of drug treatment (F(3,20) = 5.74, p < 0.05). The values indicate the mean ± SD (n = 6). * indicates a significant difference compared with the vehicle group (p < 0.05). (C) A representative photograph of the OB that indicates the microinjection site.

Mentions: In the previous section, the nasal epithelium was directly stimulated; thus, the effects identified could be mediated by these effects rather than olfaction. To further test the role of olfactory neurons in PPI, we examined the PPI response after the inactivation of OB neurons with a stereotaxic injection of either lidocaine or MK-801. Bilateral microinjections were administered in the OB of four groups of rats, including the lidocaine (n = 6), MK801 (n = 6), vehicle (n = 6) or sham surgery (n = 6) groups; the animals were then subjected to the PPI test. A repeated measures ANOVA of the data identified significant effects for drug treatment (F(3,20) = 5.74, p < 0.05) and the intensity of the auditory prepulse (F(2,40) = 1.007, p > 0.05), but not for the interaction between drug treatment and prepulse intensity (F(6,40) = 0.886, p > 0.05). Inactivation of the OB neurons by lidocaine or MK801 injection had no effect on the startle amplitude (Figure 3A), but it significantly enhanced the startle response following the prepulse (Figure 3B). The injection sites in the OB were identified using Nissl staining (Figure 3C).


Neural circuits containing olfactory neurons are involved in the prepulse inhibition of the startle reflex in rats.

Niu H, He X, Zhou T, Shi X, Zhang Q, Zhang Z, Qiao Y, Xu F, Hu M - Front Behav Neurosci (2015)

The effect of lidocaine or MK801 bilateral microinjections into the OB on the ASR and PPI. (A) Acoustic startle amplitude of the rats administered bilateral microinjections of lidocaine or MK801 in the OB. A one-way ANOVA indicated there was no significant difference between the groups. (B) The PPI (%) of the rats with the OB inhibited with lidocaine or MK801 at three different auditory prepulse intensities (70, 75 and 80 dB). A repeated measures ANOVA of the prepulse data identified significant effects of drug treatment (F(3,20) = 5.74, p < 0.05). The values indicate the mean ± SD (n = 6). * indicates a significant difference compared with the vehicle group (p < 0.05). (C) A representative photograph of the OB that indicates the microinjection site.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4373374&req=5

Figure 3: The effect of lidocaine or MK801 bilateral microinjections into the OB on the ASR and PPI. (A) Acoustic startle amplitude of the rats administered bilateral microinjections of lidocaine or MK801 in the OB. A one-way ANOVA indicated there was no significant difference between the groups. (B) The PPI (%) of the rats with the OB inhibited with lidocaine or MK801 at three different auditory prepulse intensities (70, 75 and 80 dB). A repeated measures ANOVA of the prepulse data identified significant effects of drug treatment (F(3,20) = 5.74, p < 0.05). The values indicate the mean ± SD (n = 6). * indicates a significant difference compared with the vehicle group (p < 0.05). (C) A representative photograph of the OB that indicates the microinjection site.
Mentions: In the previous section, the nasal epithelium was directly stimulated; thus, the effects identified could be mediated by these effects rather than olfaction. To further test the role of olfactory neurons in PPI, we examined the PPI response after the inactivation of OB neurons with a stereotaxic injection of either lidocaine or MK-801. Bilateral microinjections were administered in the OB of four groups of rats, including the lidocaine (n = 6), MK801 (n = 6), vehicle (n = 6) or sham surgery (n = 6) groups; the animals were then subjected to the PPI test. A repeated measures ANOVA of the data identified significant effects for drug treatment (F(3,20) = 5.74, p < 0.05) and the intensity of the auditory prepulse (F(2,40) = 1.007, p > 0.05), but not for the interaction between drug treatment and prepulse intensity (F(6,40) = 0.886, p > 0.05). Inactivation of the OB neurons by lidocaine or MK801 injection had no effect on the startle amplitude (Figure 3A), but it significantly enhanced the startle response following the prepulse (Figure 3B). The injection sites in the OB were identified using Nissl staining (Figure 3C).

Bottom Line: Our results demonstrated that blockage of olfactory sensory input could disturb olfactory behavior.In the function studies, we demonstrated that blockage of olfactory sensory input could impair the pre-pulse inhibition of the startle response following decreased c-Fos expression in relevant brain regions during the PPI responses.Thus, these data suggest that the olfactory system participates in the PPI regulating fields and plays a role in the pre-pulse inhibition of the startle response in rats.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Xuzhou Medical College Xuzhou, China ; The Institute of Audiology and Speech Science, Xuzhou Medical Collage Xuzhou, China.

ABSTRACT
Many neuropsychiatric disorders, such as schizophrenia, have been associated with olfactory dysfunction and abnormalities in the prepulse inhibition (PPI) response to a startle reflex. However, whether these two abnormalities could be related is unclear. The present investigations were designed to determine whether theblockage of olfactory sensory input by zinc sulfate infusion in the olfactory naris (0.5 ml, 0.17 M, ZnE) can disturb the PPI response. Furthermore, a bilateral microinjection of lidocaine/MK801 in the olfactory bulb (OB) was administered to examine whether the blockage of olfactory sensory input could impair the PPI response. To identify the neural projection between olfaction and PPI-related areas, trans-synaptic retrograde tracing with the recombinant pseudorabies virus (PRV) was used. Our results demonstrated that blockage of olfactory sensory input could disturb olfactory behavior. In the function studies, we demonstrated that blockage of olfactory sensory input could impair the pre-pulse inhibition of the startle response following decreased c-Fos expression in relevant brain regions during the PPI responses. Furthermore, similar and more robust findings indicated that blockage of olfactory sensory input by microinjection of lidocaine/MK801 in the OB could impair the PPI response. In the circuit-level studies, we demonstrated that trans-synaptic retrograde tracing with PRV exhibited a large portion of labeled neurons in several regions of the olfactory cortices from the pedunculopontine tegmental nucleus (PPTg). Thus, these data suggest that the olfactory system participates in the PPI regulating fields and plays a role in the pre-pulse inhibition of the startle response in rats.

No MeSH data available.


Related in: MedlinePlus