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Effect of the Non‑NMDA receptor of the glutamatergic system of the pedunculopontine tegmental nucleus(PPT) on cardiovascular responses in Normotensive and Hypotensive Rats
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Mohammad Reza Hosseiniravesh   |
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Abstract: (218 Views) |
Introduction: Glutamate is an important excitatory neurotransmitter in the pedunculopontine tegmental (PPT) nucleus. The cardiovascular effect of glutamate and its non‑N‑methyl ‑D‑aspartate (NMDA) receptor in the PPT is unknown; therefore, we evaluated glutamate and its non‑NMDA receptor on cardiovascular parameters in normotensive and hypotensive induced by hydralazine (HLZ) in the rat.
Methods and Materials: After anesthetizing the animal with urethane, the femoral artery was cannulated and the systolic pressure, mean arterial pressure, and heart rate were recorded using the Powerlab device. Intranuclear injection of drugs was performed using a stereotaxic device. L-glutamate (agonist) and CNQX (a non-NMDA receptor antagonist) alone and together with glutamate were injected into the PPT nucleus. In the next part of the study, the first lowering of blood pressure (hypotension) was caused by hydralazine and then. L-glutamate alone and CNQX (100 picomoles) alone and together with glutamate were injected. In all groups, changes (Δ) of arterial blood pressure parameters (MAP and increased systolic blood pressure) (SBP and reduced heart rate (HR)) were calculated and compared with the control group, and the corresponding graphs were recorded. First, the normality test was performed on the samples. After ensuring the normality of the data, the Paired t-test statistical method was used to compare before and after, and the unpaired t-test statistical method was used to compare two independent groups.
Results: The results of this study showed that microinjection of glutamate in the PPT nucleus significantly increased SBP, and MAP (P<0.001) and decreased HR (P<0.01) under normal conditions. Also, in the conditions of low blood pressure (hypotension) caused by hydralazine, glutamate improved hypotension. In normal conditions as well as in hypotension caused by hydralazine injection, simultaneous injection of CNQX+glutamate reduced the pressure-increasing effect caused by glutamate alone (P<0.05 to P<0.01).
Conclusion: These results show that the glutamatergic system located in the PPT nucleus plays a role in regulating cardiovascular activities in normal and hypotensive conditions. Considering that CNQX is an antagonist of non-NMAD receptors, blocking them has reduced the increasing effect of glutamate. This result confirms the presence of these receptors and their role in controlling cardiovascular activities in the PPT nucleus.
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| Keywords: CNQX, Blood pressure, NMDA and non-NMDA, Glutamate receptor, PPT |
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Full-Text [PDF 445 kb]
(27 Downloads)
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Type of Study: Research |
Subject:
General
Received: 2024/01/22 | Accepted: 2023/08/1 | Published: 2023/08/1
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