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Distribution of methionine-enkephalin in the minipig brainstem
Manuel Lisardo Sánchez1, Elena Vecino, Rafael Coveñas
1University of Salamanca, Institute of Neurosciences of Castilla y León (INCYL), Laboratory of Neuroanatomy of the Peptidergic Systems, Salamanca, Spain. lisardosanchez8@gmail.com
Abstract:
We have studied the distribution of immunoreactive cell bodies and axons are containing methionine-enkephalin in the minipig brainstem. Immunoreactive axons were widely distributed, whereas the distribution of perikarya was less widespread. A high or moderate density of axons containing methionine-enkephalin were found from rostral to caudal levels in the substantia nigra, nucleus interpeduncularis, nucleus reticularis tegmenti pontis, nucleus dorsalis raphae, nucleus centralis raphae, nuclei dorsalis and ventralis tegmenti of Gudden, locus ceruleus, nucleus sensorius principalis nervi trigemini, nucleus cuneatus externalis, nucleus tractus solitarius, nuclei vestibularis inferior and medialis, nucleus ambiguus, nucleus olivaris inferior and in the nucleus tractus spinalis nervi trigemini. Immunoreactive perikarya were observed in the nuclei centralis and dorsalis raphae, nucleus motorius nervi trigemini, nucleus centralis superior, nucleus nervi facialis, nuclei parabrachialis medialis and lateralis, nucleus ventralis raphae, nucleus reticularis lateralis and in the formatio reticularis. We have also described the presence of perikarya containing methionine-enkephalin in the nuclei nervi abducens, ruber, nervi oculomotorius and nervi trochlearis. These results suggest that in the minipig the pentapeptide may be involved in many physiological functions (for example, proprioceptive and nociceptive information; motor, respiratory and cardiovascular mechanisms).
Insights
Methionine-enkephalin is widely distributed in minipig brainstem axons, with cell bodies found in specific nuclei. This peptide likely plays a role in various physiological functions, including sensory processing and motor control.
Area of Science:
- Neuroscience
- Neuroanatomy
- Peptide Research
Background:
- Methionine-enkephalin is an endogenous opioid peptide.
- Understanding its distribution is crucial for deciphering its physiological roles.
Purpose of the Study:
- To map the distribution of methionine-enkephalin-immunoreactive cell bodies and axons in the minipig brainstem.
- To infer the potential functions of methionine-enkephalin based on its localization.
Main Methods:
- Immunohistochemistry was used to detect methionine-enkephalin.
- Brainstem sections from minipigs were analyzed for immunoreactivity.
Main Results:
- Axons containing methionine-enkephalin were found widely distributed throughout the minipig brainstem.
- Immunoreactive perikarya (cell bodies) were observed in several specific nuclei, including the raphé nuclei, pontine nuclei, and brainstem motor nuclei.
- Specific brainstem regions with high/moderate axon density include substantia nigra, locus ceruleus, and nucleus tractus solitarius.
Conclusions:
- Methionine-enkephalin is extensively present in the minipig brainstem, suggesting broad involvement in neural circuits.
- The peptide's distribution indicates potential roles in processing proprioceptive and nociceptive information, and in regulating motor, respiratory, and cardiovascular functions.
