The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
Michael H. Chase - One of the best experts on this subject based on the ideXlab platform.
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relationship between sensory stimuli elicited ipsps in motoneurons and PGO Waves during cholinergically induced muscle atonia
Journal of Neurophysiology, 1997Co-Authors: Kristi A. Kohlmeier, Francisco R. Morales, Faustino Lopezrodriguez, Michael H. ChaseAbstract:Kohlmeier, Kristi A., Faustino Lopez-Rodriguez, Francisco R. Morales, and Michael H. Chase. Relationship between sensory stimuli–elicited IPSPs in motoneurons and PGO Waves during cholinergically ...
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Relationship Between Sensory Stimuli–Elicited IPSPs in Motoneurons and PGO Waves During Cholinergically Induced Muscle Atonia
Journal of neurophysiology, 1997Co-Authors: Kristi A. Kohlmeier, Francisco R. Morales, Faustino Lopez-rodriguez, Michael H. ChaseAbstract:Kohlmeier, Kristi A., Faustino Lopez-Rodriguez, Francisco R. Morales, and Michael H. Chase. Relationship between sensory stimuli–elicited IPSPs in motoneurons and PGO Waves during cholinergically ...
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PGO-related potentials in lumbar motoneurons during active sleep.
Journal of neurophysiology, 1992Co-Authors: Faustino Lopez-rodriguez, Michael H. Chase, Francisco R. MoralesAbstract:1. The present report describes the relationship that occurs during active sleep between ponto-geniculo-occipital (PGO) Waves and changes in spinal cord motoneuron membrane potential. 2. These changes were characterized by the appearance of a complex pattern of motoneuron hyperpolarizing potentials, with a duration of approximately 300 ms, that were centered around the PGO wave. The first hyperpolarizing potential began before the onset of the PGO wave. Emerging from this hyperpolarizing potential was a second, larger-amplitude hyperpolarizing potential; it was followed by a succession of smaller-amplitude hyperpolarizations. 3. All potentials were present in conjunction with PGO Waves during active sleep, but they were observed only in some motoneurons when PGO Waves occurred during the transition period from quiet sleep to active sleep. 4. The potentials were reversed by chloride, demonstrating that they were inhibitory postsynaptic potentials (IPSPs). 5. These data, combined with the fact that these PGO-related IPSPs are blocked by strychnine, support the hypothesis that they are the result of the phasic enhancement of the activity of the same system that inhibits motoneurons during active sleep.
Larry D. Sanford - One of the best experts on this subject based on the ideXlab platform.
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Electrical stimulation of the amygdala increases the amplitude of elicited ponto-geniculo-occipital Waves.
Physiology & behavior, 1999Co-Authors: T Deboer, Richard J. Ross, Adrian R. Morrison, Larry D. SanfordAbstract:The amygdala projects massively via its central nucleus (CNA) into brain stem regions involved in alerting and ponto-geniculo-occipital (PGO) wave generation. Electrical stimulation of CNA is known to enhance the acoustic startle response (ASR) and influence spontaneous PGO Waves. The role of the amygdala in the modulation of ASR and elicited PGO Waves (PGOE) was investigated in albino rats. Electrically stimulating CNA within 25 ms prior to an auditory stimulus enhanced ASR and PGOE amplitude in a similar way, with the largest response occurring when the electrical and auditory stimuli were given simultaneously. The data suggest that CNA modulates alerting mechanisms.
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Elicited pontogeniculooccipital Waves and phasic suppression of diaphragm activity in sleep and wakefulness
Journal of applied physiology (Bethesda Md. : 1985), 1998Co-Authors: Wendy K. Hunt, Larry D. Sanford, Adrian R. Morrison, Richard J. Ross, Allan I. PackAbstract:Fractionations are 20- to 100-ms pauses in diaphragm activity that occur spontaneously during rapid-eye-movement (REM) sleep, sometimes in association with pontogeniculooccipital (PGO) Waves. Audit...
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Microinjections into the pedunculopontine tegmentum: effects of the GABAA antagonist, bicuculline, on sleep, PGO Waves and behavior.
Archives italiennes de biologie, 1998Co-Authors: Larry D. Sanford, Adrian R. Morrison, Richard J. Ross, W. K. Hunt, A. I. PackAbstract:Neurons in the peribrachial region (PB) at the pontine border are implicated in the generation of ponto-geniculo-occipital (PGO) Waves, which appear spontaneously during rapid eye movement sleep (REM) and in association with alerting behaviors during waking, as well as in the regulation of REM itself. It has been hypothesized that PGO-related bursting in a subpopulation of these neurons results from low threshold spikes triggered by phasic hyperpolarizations or by excitatory inputs reaching a steadily hyperpolarized neuron. The hyperpolarization necessary for triggering the low threshold spikes may come from local GABA neurons or from GABAergic input into PB. To test the hypothesis that antagonizing GABA would alter PGO wave generation and/or behavioral state, we microinfused, in cats, the GABAA antagonist, bicuculline, locally into PB and monitored behavior, behavioral state and PGO Waves recorded in the lateral geniculate bodies. Bicuculline produced no significant alteration in PGO wave activity. In 3 cats, bicuculline produced behaviors ranging from spontaneous orienting and startle (4 cats) to flight behaviors (2 cats) and aggressiveness (2 cats), an effect probably due to diffusion into the central gray region. Thus, the results do not support a GABAA-ergic role in PB in the generation of PGO Waves.
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Central administration of a 5-HT2 receptor agonist and antagonist: lack of effect on rapid eye movement sleep and PGO Waves.
Sleep research online : SRO, 1998Co-Authors: Larry D. Sanford, Richard J. Ross, W. K. Hunt, Allan I. Pack, Adrian R. MorrisonAbstract:Serotonin (5-HT) has a role in regulating behavioral state and controlling the production of ponto-geniculo-occipital (PGO) Waves, though the exact mechanism of action is not known. The most prevailing explanation is that 5-HT exerts its influence on behavioral state and PGO Waves by inhibiting and disinhibiting cholinergic cells in the pedunculopontine tegmentum (PPT) and laterodorsal tegmentum (LDT), which have been implicated in their generation. Recent work in rats has demonstrated 5-HT2 receptors on most cholinergic cells in PPT/LDT. We microinfused the relatively specific 5-HT2 agonist, DOI (1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane), the relatively specific 5-HT2 antagonist, ketanserin, and the nonspecific 5-HT antagonist, methysergide, locally into the peribrachial region of PPT in cats and monitored behavioral state and PGO Waves. Neither drug significantly affected behavioral state or PGO wave activity. These results suggest that 5-HT2 receptors associated with cholinergic cells are minimally involved in the control of behavioral state and, together with the recent findings of others, suggest that 5-HT may not modulate PGO wave generation via direct action on cholinergic neurons in PPT/LDT, a departure from the long-held but minimally-tested view.
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Elicited PGO Waves in rats: Lack of 5-HT1A inhibition in putative pontine generator region
Pharmacology biochemistry and behavior, 1996Co-Authors: Larry D. Sanford, Richard J. Ross, Shanaz M. Tejani-butt, Adrian R. MorrisonAbstract:Abstract Ponto-geniculo-occipital (PGO) Waves and an elicited analogue (PGO E ) may be recorded in the pons of rats. Cholinergic cells in the pedunculopontine tegmental (PPT) and laterodorsal tegmental (LDT) nuclei are implicated in the generation of PGO Waves. Serotonin (5-HT) may inhibit the generation of PGO Waves, and possibly PGO E . We examined the role of 5-HT 1A receptor mechanisms in the generation of auditory-elicited PGO E in rats. Administration of 8-OH-DPAT [8-hydroxy-2-( n -dipropylamino) tetralin] into PPT did not significantly affect PGO E amplitude or response frequency. Binding of [ 3 H]CN-IMI ([ 3 H]cyanoimipramine) to 5-HT uptake sites located presynaptically was used as a measure of 5-HT innervation. Quantitative autoradiographic analysis of [ 3 H]CN-IMI binding indicated a moderate to low degree of 5-HT innervation of PPT and a moderately high innervation of LDT compared to the dorsal raphe nucleus (DRN). Binding of [ 3 H]8-OH-DPAT to 5-HT 1A receptors revealed few receptor sites in PPT, and a low to moderate number of receptors in LDT compared to binding in DRN. The results suggest that inhibitory serotonergic modulation of PGO E is probably not mediated through a 5-HT 1A receptor mechanism in PPT.
Adrian R. Morrison - One of the best experts on this subject based on the ideXlab platform.
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You Have Interpreted the PGO Waves of REM Sleep as Activation of the Startle Network of the Brain. What Is Your Theory of the Function of Off-Line Startle and What Impact, If Any, Does This Activation Have Upon Dreaming?
Dream Consciousness, 2014Co-Authors: Adrian R. MorrisonAbstract:In 1976, Bob Bowker and I reported that Waves seemingly identical to spontaneous PGO Waves (usually called spikes then) could be elicited by sounds in REM sleep as well as NREM sleep. We proposed that ponto-geniculo-occipital (PGO) Waves were probably evidence of the spontaneous excitation of the startle network. This conclusion stemmed from Dement’s report that cats under the influence of the anti-serotonergic drug, p-chlorophenylalanine (PCPA), startled every time a PGO wave occurred when they were “awake.” We later changed from “startle” to “alerting” because we considered that the Waves reflected the activation of a system responsible for detection of a stimulus, fundamental to the organization of the critical behavioral response of orienting, with startle being a less organized expression of a response to an unexpected stimulus. The focus on eye activity and dreams may have led other workers away from what is in our opinion their real significance: a sign of internal alerting in the brain (as distinct from behavioral arousal), a fundamental and “peculiar” aspect of REM sleep.
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Electrical stimulation of the amygdala increases the amplitude of elicited ponto-geniculo-occipital Waves.
Physiology & behavior, 1999Co-Authors: T Deboer, Richard J. Ross, Adrian R. Morrison, Larry D. SanfordAbstract:The amygdala projects massively via its central nucleus (CNA) into brain stem regions involved in alerting and ponto-geniculo-occipital (PGO) wave generation. Electrical stimulation of CNA is known to enhance the acoustic startle response (ASR) and influence spontaneous PGO Waves. The role of the amygdala in the modulation of ASR and elicited PGO Waves (PGOE) was investigated in albino rats. Electrically stimulating CNA within 25 ms prior to an auditory stimulus enhanced ASR and PGOE amplitude in a similar way, with the largest response occurring when the electrical and auditory stimuli were given simultaneously. The data suggest that CNA modulates alerting mechanisms.
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Elicited pontogeniculooccipital Waves and phasic suppression of diaphragm activity in sleep and wakefulness
Journal of applied physiology (Bethesda Md. : 1985), 1998Co-Authors: Wendy K. Hunt, Larry D. Sanford, Adrian R. Morrison, Richard J. Ross, Allan I. PackAbstract:Fractionations are 20- to 100-ms pauses in diaphragm activity that occur spontaneously during rapid-eye-movement (REM) sleep, sometimes in association with pontogeniculooccipital (PGO) Waves. Audit...
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Microinjections into the pedunculopontine tegmentum: effects of the GABAA antagonist, bicuculline, on sleep, PGO Waves and behavior.
Archives italiennes de biologie, 1998Co-Authors: Larry D. Sanford, Adrian R. Morrison, Richard J. Ross, W. K. Hunt, A. I. PackAbstract:Neurons in the peribrachial region (PB) at the pontine border are implicated in the generation of ponto-geniculo-occipital (PGO) Waves, which appear spontaneously during rapid eye movement sleep (REM) and in association with alerting behaviors during waking, as well as in the regulation of REM itself. It has been hypothesized that PGO-related bursting in a subpopulation of these neurons results from low threshold spikes triggered by phasic hyperpolarizations or by excitatory inputs reaching a steadily hyperpolarized neuron. The hyperpolarization necessary for triggering the low threshold spikes may come from local GABA neurons or from GABAergic input into PB. To test the hypothesis that antagonizing GABA would alter PGO wave generation and/or behavioral state, we microinfused, in cats, the GABAA antagonist, bicuculline, locally into PB and monitored behavior, behavioral state and PGO Waves recorded in the lateral geniculate bodies. Bicuculline produced no significant alteration in PGO wave activity. In 3 cats, bicuculline produced behaviors ranging from spontaneous orienting and startle (4 cats) to flight behaviors (2 cats) and aggressiveness (2 cats), an effect probably due to diffusion into the central gray region. Thus, the results do not support a GABAA-ergic role in PB in the generation of PGO Waves.
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Central administration of a 5-HT2 receptor agonist and antagonist: lack of effect on rapid eye movement sleep and PGO Waves.
Sleep research online : SRO, 1998Co-Authors: Larry D. Sanford, Richard J. Ross, W. K. Hunt, Allan I. Pack, Adrian R. MorrisonAbstract:Serotonin (5-HT) has a role in regulating behavioral state and controlling the production of ponto-geniculo-occipital (PGO) Waves, though the exact mechanism of action is not known. The most prevailing explanation is that 5-HT exerts its influence on behavioral state and PGO Waves by inhibiting and disinhibiting cholinergic cells in the pedunculopontine tegmentum (PPT) and laterodorsal tegmentum (LDT), which have been implicated in their generation. Recent work in rats has demonstrated 5-HT2 receptors on most cholinergic cells in PPT/LDT. We microinfused the relatively specific 5-HT2 agonist, DOI (1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane), the relatively specific 5-HT2 antagonist, ketanserin, and the nonspecific 5-HT antagonist, methysergide, locally into the peribrachial region of PPT in cats and monitored behavioral state and PGO Waves. Neither drug significantly affected behavioral state or PGO wave activity. These results suggest that 5-HT2 receptors associated with cholinergic cells are minimally involved in the control of behavioral state and, together with the recent findings of others, suggest that 5-HT may not modulate PGO wave generation via direct action on cholinergic neurons in PPT/LDT, a departure from the long-held but minimally-tested view.
Graziella L. Mann - One of the best experts on this subject based on the ideXlab platform.
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Central administration of two 5-HT receptor agonists: effect on REM sleep initiation and PGO Waves.
Pharmacology biochemistry and behavior, 1994Co-Authors: Larry D. Sanford, Adrian R. Morrison, William A. Ball, Richard J. Ross, Amalia E. Seggos, Graziella L. MannAbstract:Cholinergic neurons in the pedunculopontine tegmental (PPT) and the laterodorsal tegmental (LDT) nuclei are implicated in the generation of rapid eye movement sleep (REM) and ponto-geniculo-occipital (PGO) Waves. Serotonin (5-HT) has a role in sleep-wake regulation and appears to inhibit PGO wave generation. We studied the effects of the central infusion of the relatively specific 5-HT1A receptor agonist 8-hydroxy-2-(n-dipropylamino)tetralin (DPAT) and the less specific 5-HT1 receptor agonist 1(3-chlorophenyl)piperazine (mCPP) on the regulation of REM and on PGO wave generation. DPAT (0.0, 0.002, 0.01, 0.08, and 0.8 microgram/0.5 microliter normal saline) and mCPP (0.0, 0.02, 0.2, 2.0, and 20.0 micrograms/0.5 microliter normal saline) were infused unilaterally into the peribrachial region of PPT (PB) in cats. Additionally, DPAT (0.01 microgram/0.5 microliter) was infused bilaterally into PB in a separate experiment. Low dosages of DPAT (unilateral or bilateral) decreased successful entrances into REM (0.01 microgram) and time spent asleep (0.002 microgram and 0.01 microgram) without affecting outward behavior. No dosage of mCPP significantly decreased the number of REM episodes, and neither drug decreased REM episode duration once REM had been entered. Neither drug affected the rate of PGO Waves independently of modulating behavioral state. We propose that 5-HT1A receptor mechanisms have an inhibitory role in actual REM initiation, possibly by facilitating endogenously generated excitation of brainstem startle mechanisms at the onset of REM.
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Sleep patterning and behaviour in cats with pontine lesions creating REM without atonia
Journal of sleep research, 1994Co-Authors: Larry D. Sanford, Adrian R. Morrison, Graziella L. Mann, Js Harris, L Yoo, Richard J. RossAbstract:Lesions of the dorsal pontine tegmentum release muscle tone and motor behaviour, much of it similar to orienting during wakefulness, into rapid eye movement sleep (REM), a state normally characterized by paralysis. Sleep after pontine lesions may be altered, with more REM-A episodes of shorter duration compared to normal REM. We examined behaviour, ponto-geniculo-occipital (PGO) Waves (which may be central markers of orienting) and sleep in lesioned cats: (i) to characterize the relationship of PGO Waves to behaviour in REM-A; (ii) to determine whether post-lesion changes in the timing and duration of REM-A episodes were due to activity-related awakenings: and (iii) to determine whether alterations in sleep changed the circadian sleep/wake cycle in cats. Behavioural release in REM-A was generally related to episode length, but episode length was not necessarily shorter than normal REM in cats capable of full locomotion in REM-A. PGO wave frequency was reduced overall during REM-A, but was higher during REM-A with behaviour than during quiet REM-A without overt behaviour. Pontine lesions did not significantly alter the circadian sleep/wake cycle: REM-A had approximately the same Light/Dark distribution as normal REM. Differences in the patterning of normal REM and REM-A within sleep involve more than mere movement-induced awakenings. Brainstem lesions that eliminate the atonia of REM may damage neural circuitry involved in REM initiation and maintenance; this circuitry is separate from circadian control mechanisms.
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The amplitude of elicited PGO Waves: a correlate of orienting
Electroencephalography and clinical neurophysiology, 1993Co-Authors: Larry D. Sanford, Adrian R. Morrison, William A. Ball, Richard J. Ross, Graziella L. MannAbstract:Ponto-geniculo-occipital (PGO) Waves spontaneously occur in the pons, lateral geniculate body (LGB), and occipital cortex during rapid eye movement sleep (REM), and PGO-like Waves (PGOE) may be elicited in LGB during sleep and waking. Because REM has been hypothesized to be a state of continual "orienting" or "hyper-alertness," we tested whether the amplitudes of PGOE in "alerting" situations (the abrupt onset of a loud sound or presentation of a novel stimulus within a series of stimuli) that evoke orienting responses (OR) would be greater than those following stimuli without OR. We also compared PGOE accompanying OR to PGOE during REM and NREM when OR are absent. The amplitudes of PGOE in W were greatest when OR were observed, and the amplitudes of PGOE accompanying OR were not significantly different from PGOE amplitudes in REM. Likewise, the amplitudes of PGOE during REM were not significantly different from those of the highest amplitude spontaneous PGO Waves. We propose that the presence of PGOE signals registration of stimuli and that stimuli of sufficient significance to induce behavioral OR in waking also elicit PGOE of significantly greater amplitudes in all behavioral states. These findings support the hypothesis that the presence of high-amplitude PGO Waves in REM indicates that the brain is in a state of more-or-less continual orienting.
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Spontaneous phasic activity in the brain: differences between Waves in lateral geniculate and central lateral nuclei across sleep states.
Journal of sleep research, 1992Co-Authors: Larry D. Sanford, Adrian R. Morrison, William A. Ball, Richard J. Ross, Graziella L. MannAbstract:SUMMARY Ponto-geniculo-occipital (PGO) Waves are spontaneously-occurring macropotential waveforms recorded in the pons, lateral geniculate body (LGB) and occipital cortex. PGO Waves mark the onset and course of rapid eye movement sleep (REM). PGO-like Waves can be recorded in several brain areas including the thalamic central lateral nucleus (CL). Alerting stimuli elicit PGO Waves (PGOE) from LGB and Waves from CL (CLE) in all behavioural states. We compared spontaneous activity in LGB and CL across behavioral states to examine the relationship of CL Waves to PGO Waves. Spontaneous Waves in LGB and CL may occur concurrently or separately in all states. Although REM is marked by a high level of LGB PGO activity, CL Waves are rare. Frequencies of CL and LGB Waves are similar in non-REM (NREM) although the Waves do not necessarily occur at the same time. These findings suggest that the widespread phasic activity recorded throughout the brain in sleep cannot be assumed to be a non-specific unitary phenomenon propagated from a single brainstem generator.
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Peripheral and central components of alerting: habituation of acoustic startle, orienting responses, and elicited waveforms.
Behavioral neuroscience, 1992Co-Authors: Larry D. Sanford, Adrian R. Morrison, William A. Ball, Richard J. Ross, Graziella L. MannAbstract:Behavioral orienting (OR), the acoustic startle reflex (ASR), pontogeniculooccipital (PGO) Waves in the lateral geniculate body, and midlatency auditory evoked responses (MLR) represent components of alerting. The habituation rate for each was examined to test the hypothesis that OR, ASR, and PGO Waves have related underlying neural mechanisms and determine the similarity in responsiveness between elicited PGO Waves (PGOE) and elicited Waves in the thalamic central lateral nucleus (CLE), a site that yields MLR. PGOE and CLE Waves did not habituate in amplitude after 120 tones; however, the pattern of responses for each waveform was different. OR and ASR significantly decreased amplitude across trials with OR exhibiting a faster, more pronounced decrement. Some separation exists between the peripheral (OR and ASR) and central (PGOE and CLE) components of alerting. PGO and CL Waves may have common underlying neural mechanisms.
Richard J. Ross - One of the best experts on this subject based on the ideXlab platform.
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Electrical stimulation of the amygdala increases the amplitude of elicited ponto-geniculo-occipital Waves.
Physiology & behavior, 1999Co-Authors: T Deboer, Richard J. Ross, Adrian R. Morrison, Larry D. SanfordAbstract:The amygdala projects massively via its central nucleus (CNA) into brain stem regions involved in alerting and ponto-geniculo-occipital (PGO) wave generation. Electrical stimulation of CNA is known to enhance the acoustic startle response (ASR) and influence spontaneous PGO Waves. The role of the amygdala in the modulation of ASR and elicited PGO Waves (PGOE) was investigated in albino rats. Electrically stimulating CNA within 25 ms prior to an auditory stimulus enhanced ASR and PGOE amplitude in a similar way, with the largest response occurring when the electrical and auditory stimuli were given simultaneously. The data suggest that CNA modulates alerting mechanisms.
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Elicited pontogeniculooccipital Waves and phasic suppression of diaphragm activity in sleep and wakefulness
Journal of applied physiology (Bethesda Md. : 1985), 1998Co-Authors: Wendy K. Hunt, Larry D. Sanford, Adrian R. Morrison, Richard J. Ross, Allan I. PackAbstract:Fractionations are 20- to 100-ms pauses in diaphragm activity that occur spontaneously during rapid-eye-movement (REM) sleep, sometimes in association with pontogeniculooccipital (PGO) Waves. Audit...
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Microinjections into the pedunculopontine tegmentum: effects of the GABAA antagonist, bicuculline, on sleep, PGO Waves and behavior.
Archives italiennes de biologie, 1998Co-Authors: Larry D. Sanford, Adrian R. Morrison, Richard J. Ross, W. K. Hunt, A. I. PackAbstract:Neurons in the peribrachial region (PB) at the pontine border are implicated in the generation of ponto-geniculo-occipital (PGO) Waves, which appear spontaneously during rapid eye movement sleep (REM) and in association with alerting behaviors during waking, as well as in the regulation of REM itself. It has been hypothesized that PGO-related bursting in a subpopulation of these neurons results from low threshold spikes triggered by phasic hyperpolarizations or by excitatory inputs reaching a steadily hyperpolarized neuron. The hyperpolarization necessary for triggering the low threshold spikes may come from local GABA neurons or from GABAergic input into PB. To test the hypothesis that antagonizing GABA would alter PGO wave generation and/or behavioral state, we microinfused, in cats, the GABAA antagonist, bicuculline, locally into PB and monitored behavior, behavioral state and PGO Waves recorded in the lateral geniculate bodies. Bicuculline produced no significant alteration in PGO wave activity. In 3 cats, bicuculline produced behaviors ranging from spontaneous orienting and startle (4 cats) to flight behaviors (2 cats) and aggressiveness (2 cats), an effect probably due to diffusion into the central gray region. Thus, the results do not support a GABAA-ergic role in PB in the generation of PGO Waves.
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Central administration of a 5-HT2 receptor agonist and antagonist: lack of effect on rapid eye movement sleep and PGO Waves.
Sleep research online : SRO, 1998Co-Authors: Larry D. Sanford, Richard J. Ross, W. K. Hunt, Allan I. Pack, Adrian R. MorrisonAbstract:Serotonin (5-HT) has a role in regulating behavioral state and controlling the production of ponto-geniculo-occipital (PGO) Waves, though the exact mechanism of action is not known. The most prevailing explanation is that 5-HT exerts its influence on behavioral state and PGO Waves by inhibiting and disinhibiting cholinergic cells in the pedunculopontine tegmentum (PPT) and laterodorsal tegmentum (LDT), which have been implicated in their generation. Recent work in rats has demonstrated 5-HT2 receptors on most cholinergic cells in PPT/LDT. We microinfused the relatively specific 5-HT2 agonist, DOI (1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane), the relatively specific 5-HT2 antagonist, ketanserin, and the nonspecific 5-HT antagonist, methysergide, locally into the peribrachial region of PPT in cats and monitored behavioral state and PGO Waves. Neither drug significantly affected behavioral state or PGO wave activity. These results suggest that 5-HT2 receptors associated with cholinergic cells are minimally involved in the control of behavioral state and, together with the recent findings of others, suggest that 5-HT may not modulate PGO wave generation via direct action on cholinergic neurons in PPT/LDT, a departure from the long-held but minimally-tested view.
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Elicited PGO Waves in rats: Lack of 5-HT1A inhibition in putative pontine generator region
Pharmacology biochemistry and behavior, 1996Co-Authors: Larry D. Sanford, Richard J. Ross, Shanaz M. Tejani-butt, Adrian R. MorrisonAbstract:Abstract Ponto-geniculo-occipital (PGO) Waves and an elicited analogue (PGO E ) may be recorded in the pons of rats. Cholinergic cells in the pedunculopontine tegmental (PPT) and laterodorsal tegmental (LDT) nuclei are implicated in the generation of PGO Waves. Serotonin (5-HT) may inhibit the generation of PGO Waves, and possibly PGO E . We examined the role of 5-HT 1A receptor mechanisms in the generation of auditory-elicited PGO E in rats. Administration of 8-OH-DPAT [8-hydroxy-2-( n -dipropylamino) tetralin] into PPT did not significantly affect PGO E amplitude or response frequency. Binding of [ 3 H]CN-IMI ([ 3 H]cyanoimipramine) to 5-HT uptake sites located presynaptically was used as a measure of 5-HT innervation. Quantitative autoradiographic analysis of [ 3 H]CN-IMI binding indicated a moderate to low degree of 5-HT innervation of PPT and a moderately high innervation of LDT compared to the dorsal raphe nucleus (DRN). Binding of [ 3 H]8-OH-DPAT to 5-HT 1A receptors revealed few receptor sites in PPT, and a low to moderate number of receptors in LDT compared to binding in DRN. The results suggest that inhibitory serotonergic modulation of PGO E is probably not mediated through a 5-HT 1A receptor mechanism in PPT.