Nociceptive-Nociceptive-antinociceptive antinociceptive

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Physiological importance of Physiological importance of pain pain

► According to modern notion, pain is subjective According to modern notion, pain is subjective perception of systemic processes, which perception of systemic processes, which include information about tissue damage. include information about tissue damage. Activation of pain receptors leads to starting Activation of pain receptors leads to starting different protective reflexes to avoid tissue different protective reflexes to avoid tissue damage. However, pain is unpleasant sense damage. However, pain is unpleasant sense and involve to pain reaction wide net of and involve to pain reaction wide net of regulative and homeostatic systems of human regulative and homeostatic systems of human organism. organism.

► The important specialty in reaction to pain in The important specialty in reaction to pain in human is participation of brain cortex and human is participation of brain cortex and limbic system, which leads to severe emotional limbic system, which leads to severe emotional experience and autonomic reactions. experience and autonomic reactions.

CChanges in human organism hanges in human organism followfollowinging pain pain

►Nociceptive reactions are accompanied by Nociceptive reactions are accompanied by motion reactions of entire body towards motion reactions of entire body towards avoidance the pain. avoidance the pain.

► In human organism such motion reactions for In human organism such motion reactions for the some part presented by unconditioned the some part presented by unconditioned reflexes with short reflector arc formed by reflexes with short reflector arc formed by neurons of spinal cord and brain stem. But neurons of spinal cord and brain stem. But majority of that are behavioral and emotional majority of that are behavioral and emotional reactions, which based on conditional reflexes. reactions, which based on conditional reflexes.

► That is why reflector arc includes besides That is why reflector arc includes besides neurons of spinal cord and brain stem neurons of spinal cord and brain stem structures of limbic-reticular complex and structures of limbic-reticular complex and brain cortex. brain cortex.

► Also different changes Also different changes in human organism in human organism followed by pain are followed by pain are observed: increase of observed: increase of muscle tone, muscle tone, accelerated heartbeat, accelerated heartbeat, increase of blood increase of blood pressure, pressure, intensification of intensification of sweating, dilatation of sweating, dilatation of pupils and elevation of pupils and elevation of glucose and cuprum glucose and cuprum level in plasma, level in plasma, activation of activation of hemostasis.hemostasis.

► It considered to cause It considered to cause the majority of both the majority of both visceral and visceral and biochemical reactions biochemical reactions by excitation of by excitation of sympathetic nervous sympathetic nervous system, which is system, which is presented by neurons presented by neurons of hypothalamus, of hypothalamus, hypophisis and cells in hypophisis and cells in medullar substance of medullar substance of adrenal glands.adrenal glands.

Pain and stress reactionPain and stress reaction► In fact tissue damage and pain triggers the stress reaction - In fact tissue damage and pain triggers the stress reaction -

common reaction of an organism, which leads to stimulation all common reaction of an organism, which leads to stimulation all the functions, especially motion and that is why blood the functions, especially motion and that is why blood circulation due to cardiovascular system, metabolism, transport circulation due to cardiovascular system, metabolism, transport of gases due to activation of breathing. Stimulation of pituitary-of gases due to activation of breathing. Stimulation of pituitary-adrenal axis increases secretion of adrenocorticotropic adrenal axis increases secretion of adrenocorticotropic hormone from the anterior pituitary, and thus there is hormone from the anterior pituitary, and thus there is increased secretion of glucocorticoides from the adrenal cortex. increased secretion of glucocorticoides from the adrenal cortex. That is why functions of organism activate to defend one. That is why functions of organism activate to defend one.

► But long lasting stress reaction is rather dangerous for But long lasting stress reaction is rather dangerous for organism. Adrenalin in high concentration may produce organism. Adrenalin in high concentration may produce decreasing of blood supply in visceral organs, which leads to decreasing of blood supply in visceral organs, which leads to metabolic disorders and disturbances of its function. Besides metabolic disorders and disturbances of its function. Besides that nociceptive nerve endings in damaged tissues produce a that nociceptive nerve endings in damaged tissues produce a lot of nervous impulses, which spreading into central nervous lot of nervous impulses, which spreading into central nervous system activates wide net of nervous cells. This considerable system activates wide net of nervous cells. This considerable excitation leads to disturbances in nervous regulation of all excitation leads to disturbances in nervous regulation of all functions in human organism. functions in human organism.

Pain and diagnosingPain and diagnosing

► Pain gives useful information about cause of Pain gives useful information about cause of tissue damage. When determining the origin tissue damage. When determining the origin of pain it is important to special fiches of of pain it is important to special fiches of pain. pain.

► It is necessary pay attention for location, It is necessary pay attention for location, character, duration, motion and visceral character, duration, motion and visceral reactions and subjective sensations, reactions and subjective sensations, following the pain. following the pain.

► It is considered, after diagnosing pain must It is considered, after diagnosing pain must be removed. be removed.

Ranks of pain Ranks of pain

► According to location of pain: somatic and According to location of pain: somatic and visceral.visceral.

► According to time of appearance of pain According to time of appearance of pain after tissue damage: early and late pain.after tissue damage: early and late pain.

► According to subjective sensation (or According to subjective sensation (or character): acute or burning, dull or spread.character): acute or burning, dull or spread.

► According to duration: sort or prolonged According to duration: sort or prolonged pain attacks. pain attacks.

► Subjective sensations in pain may be Subjective sensations in pain may be presented emotional experience as terror, presented emotional experience as terror, worry, visual hallucination, dizziness, which worry, visual hallucination, dizziness, which appears before of followed the pain.appears before of followed the pain.

Reflected painReflected pain

► Reflected pain is caused by irritation of visceral Reflected pain is caused by irritation of visceral organs. Such events as strong constriction of organs. Such events as strong constriction of smooth muscles; disorders of blood supply; tension smooth muscles; disorders of blood supply; tension of vessels, stomach, intestines result in pain in of vessels, stomach, intestines result in pain in certain parts of body. It is determined sensor certain parts of body. It is determined sensor neurons to connect through interneurons with neurons to connect through interneurons with autonomic and motor neurons in spinal cord. In such autonomic and motor neurons in spinal cord. In such a way, viscerosomatic autonomic reflexes are a way, viscerosomatic autonomic reflexes are realized. realized.

► Due to mentioned intracellular contacts, human Due to mentioned intracellular contacts, human capable to locate nociceptive sensation. These capable to locate nociceptive sensation. These zones of human body where impulses from certain zones of human body where impulses from certain visceral organs are reflected called as Zacharjin-Ged visceral organs are reflected called as Zacharjin-Ged zones. For example, in stomach disorders a human zones. For example, in stomach disorders a human fells pain around navel. Acute pain caused by blood fells pain around navel. Acute pain caused by blood supply disorders in heart muscle reflected to the left supply disorders in heart muscle reflected to the left shoulder, left shoulder blade and left epigastria. shoulder, left shoulder blade and left epigastria.

Pain reception Pain reception

► Damage stimuli perception created by the brain Damage stimuli perception created by the brain from electrochemical nerve impulses delivered to it from electrochemical nerve impulses delivered to it from sensory receptors. These receptors transfuse from sensory receptors. These receptors transfuse (or change) different influences of both internal (or change) different influences of both internal processes in organism and surrounding processes in organism and surrounding environment into the electric impulses.environment into the electric impulses.

► Pain receptors are specific. Pain does not appear in Pain receptors are specific. Pain does not appear in hyperstimulation of improper receptors. On other hyperstimulation of improper receptors. On other handhand,, adequate stimuli are not so specific as for adequate stimuli are not so specific as for other sensations. That is why pain receptors maybe other sensations. That is why pain receptors maybe stimulated by different kind of irritations. stimulated by different kind of irritations.

► Pain receptors may react also to electric, mechanic Pain receptors may react also to electric, mechanic and especially chemical energy. and especially chemical energy.

► Afferent nociceptive Afferent nociceptive impulses are collected into impulses are collected into central nervous system by central nervous system by two kinds of nervous fibers: two kinds of nervous fibers: quick a-delta myelinated quick a-delta myelinated nerve fibers and C-fibers nerve fibers and C-fibers without myelin. without myelin.

► The ascending fibers are The ascending fibers are included in spinothalamic included in spinothalamic tract, which passes through tract, which passes through the spinal cord and reach the spinal cord and reach medulla oblongata. Here medulla oblongata. Here there are second order there are second order sensory neurons of sensory neurons of spinomesencephalic tract.spinomesencephalic tract.

► Fibers of spinothalamic Fibers of spinothalamic tract synapse with third-tract synapse with third-order neurons in the order neurons in the thalamus, which in turn thalamus, which in turn project to the postcentral project to the postcentral gyrus of the contralateral gyrus of the contralateral cerebral hemisphere.cerebral hemisphere.

Nociceptive structures in central nervous Nociceptive structures in central nervous

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► Information about the pain from head, Information about the pain from head, face and mouth cavity ascend to central face and mouth cavity ascend to central nervous system by sensory fibers of nervous system by sensory fibers of cranial nerves, for instance facial, cranial nerves, for instance facial, glossopharyngeal, vagus and trigeminus glossopharyngeal, vagus and trigeminus nerves.nerves.

►Central nociceptive neurons lay in Central nociceptive neurons lay in nucleus of thalamus, hypothalamus, nucleus of thalamus, hypothalamus, midencephalon central gray substance, midencephalon central gray substance, reticular formation and somatosensoric reticular formation and somatosensoric fields of brain cortex.fields of brain cortex.

Anti-nociceptive system Anti-nociceptive system

► To antinociceptive neuro-endocrine system To antinociceptive neuro-endocrine system belong nervous structures, which are belong nervous structures, which are concentrated, obviously, in brain stem. concentrated, obviously, in brain stem.

► High intensity of pain stimuli permits activation High intensity of pain stimuli permits activation of these structures, which contain neurons of these structures, which contain neurons capable to release endogenous opioids. capable to release endogenous opioids.

► To such structure belong, for instance, To such structure belong, for instance, prefrontal cortex, hypothalamus, central gray prefrontal cortex, hypothalamus, central gray substance, medial thalamic nuclei and limbic substance, medial thalamic nuclei and limbic system. system.

Role of opioid peptides Role of opioid peptides

► In brain and digestive tract are located receptors, In brain and digestive tract are located receptors, which bind to morphine. Investigation endogenous which bind to morphine. Investigation endogenous ligands of these receptors give ability to reveal two ligands of these receptors give ability to reveal two similar pentapeptides, called encephalines, which similar pentapeptides, called encephalines, which bind to opioid receptors: met-encephalin and ley-bind to opioid receptors: met-encephalin and ley-encepfalin. Such chemicals are known as opioid encepfalin. Such chemicals are known as opioid peptides. peptides.

► Encephalines are containing in nerve endings of Encephalines are containing in nerve endings of digestive tract and many parts in brain. It function digestive tract and many parts in brain. It function as neurotransmitters. These peptides are present in as neurotransmitters. These peptides are present in gelatinous substance. gelatinous substance.

► In injecting into brain stem, opioid peptides In injecting into brain stem, opioid peptides manifestate analgetic effect. Encephalines also may manifestate analgetic effect. Encephalines also may slow down intestines peristaltic.slow down intestines peristaltic.

Analgesia with drugsAnalgesia with drugs

► Drugs may influence in different levels. It is known Drugs may influence in different levels. It is known local analgesia by inactivation of nociceptors using local analgesia by inactivation of nociceptors using chloraethil or by injection of analgesic in tissues chloraethil or by injection of analgesic in tissues adjacent to nervous fibers. Novocain, analgin and adjacent to nervous fibers. Novocain, analgin and other medicines may prevent generation and other medicines may prevent generation and spreading of nervous impulses by temporarily spreading of nervous impulses by temporarily inactivation of ion gates. inactivation of ion gates.

► Some drugs may be injected in the lumbal space. In Some drugs may be injected in the lumbal space. In this case spreading impulses through ascendant this case spreading impulses through ascendant conduction is obtained. In using common analgesia conduction is obtained. In using common analgesia braking activity of central neurons leads to both braking activity of central neurons leads to both analgesia and unconsciousness, which cold surgical analgesia and unconsciousness, which cold surgical sleep. sleep.

► There are some drugs, capable modulate activity of There are some drugs, capable modulate activity of limbic system and cause sedative effect.limbic system and cause sedative effect.

Electrostimulation for Electrostimulation for analgesiaanalgesia

► Electrostimulation through skin or Electrostimulation through skin or incorporated electrodes into sensory tracts incorporated electrodes into sensory tracts and nucleus is used for analgesia. and nucleus is used for analgesia. Acupuncture, electro puncture and other Acupuncture, electro puncture and other methods of reflex therapy are also effective methods of reflex therapy are also effective approaches to analgesia. approaches to analgesia.

► It considered causing analgesic effect by It considered causing analgesic effect by beta-endorphin secretion stimulation in beta-endorphin secretion stimulation in hypotalamo-hypophisal system, which may hypotalamo-hypophisal system, which may block nociceptive impulses in the way to block nociceptive impulses in the way to higher nervous centers. higher nervous centers.

► Last time artificial hypothermia or Last time artificial hypothermia or hybernacia, which is cold analgesia, is used.hybernacia, which is cold analgesia, is used.

PPsychological methods reliving sychological methods reliving painpain

►Every people can use psychological Every people can use psychological methods reliving pain by switching methods reliving pain by switching attention over pain for instance. In long attention over pain for instance. In long duration of chronicle pain, sensation duration of chronicle pain, sensation becomes blunt. Today psychological becomes blunt. Today psychological therapy of pain is more spread. For this therapy of pain is more spread. For this purpose, biological reverse connection purpose, biological reverse connection may be used. may be used.

►This method proposed to relive chronicle This method proposed to relive chronicle pain, migraine attack for instance pain, migraine attack for instance

Cutting off nociceptive conduction bundlesCutting off nociceptive conduction bundles

► To surgical methods of treatment in connection with pain To surgical methods of treatment in connection with pain belongs cutting off corresponding sensory nerve upper the belongs cutting off corresponding sensory nerve upper the origin place of pain. It is used peripheral neurotomia, cutting origin place of pain. It is used peripheral neurotomia, cutting off nociceptive conduction bundles in spinal cord (lobotomy, off nociceptive conduction bundles in spinal cord (lobotomy, comissurotomy or bulbar tractotomy).comissurotomy or bulbar tractotomy).

► Special place engaged by operations on the brain. The main Special place engaged by operations on the brain. The main purpose of such operations is breaking connections between purpose of such operations is breaking connections between the brain cortex and thalamus, because it determined the the brain cortex and thalamus, because it determined the brain cortex to bi responsible for subjective pain sensation brain cortex to bi responsible for subjective pain sensation formation. To such operations belongs stereotaxic operation formation. To such operations belongs stereotaxic operation on thalamus nuclei (thalamaectomy), splitting of nervous on thalamus nuclei (thalamaectomy), splitting of nervous fibers in the depth of frontal part of brain, which connect it fibers in the depth of frontal part of brain, which connect it with thalamus (frontal lobaectimy), cortex removal in gyrus with thalamus (frontal lobaectimy), cortex removal in gyrus postcentralis and adjacent parts of parietal lobe, temporal postcentralis and adjacent parts of parietal lobe, temporal cortex and lover parts of frontal lobe. It is necessary to point cortex and lover parts of frontal lobe. It is necessary to point attention to use last group of analgesic methods in extreme attention to use last group of analgesic methods in extreme situations only. situations only.

► When other methods will not be effective, patient may be When other methods will not be effective, patient may be operated. However, field of operations in pain manifestation operated. However, field of operations in pain manifestation is considerably wider and is not limited by operations on is considerably wider and is not limited by operations on nervous system.nervous system.