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Varlinskaya EI, Johnson JM, Przybysz KR, Deak T, Diaz MR. Adolescent forced swim stress increases social anxiety-like behaviors and alters kappa opioid receptor function in the basolateral amygdala of male rats. Prog Neuropsychopharmacol Biol Psychiatry 2020; 98:109812. [PMID: 31707090 PMCID: PMC6920550 DOI: 10.1016/j.pnpbp.2019.109812] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 12/15/2022]
Abstract
Adolescence is a developmental period marked by robust neural alterations and heightened vulnerability to stress, a factor that is highly associated with increased risk for emotional processing deficits, such as anxiety. Stress-induced upregulation of the dynorphin/kappa opioid receptor (DYN/KOP) system is thought to, in part, underlie the negative affect associated with stress. The basolateral amygdala (BLA) is a key structure involved in anxiety, and neuromodulatory systems, such as the DYN/KOP system, can 1) regulate BLA neural activity in an age-dependent manner in stress-naïve animals and 2) underlie stress-induced anxiety in adults. However, the role of the DYN/KOP system in modulating stress-induced anxiety in adolescents is unknown. To test this, we examined the impact of an acute, 2-day forced swim stress (FSS - 10 min each day) on adolescent (~postnatal day (P) 35) and adult Sprague-Dawley rats (~P70), followed by behavioral, molecular and electrophysiological assessment 24 h following FSS. Adolescent males, but not adult males or females of either age, demonstrated social anxiety-like behavioral alterations indexed via significantly reduced social investigation and preference when tested 24 h following FSS. Conversely, adult males exhibited increased social preference. While there were no FSS-induced changes in expression of genes related to the DYN/KOP system in the BLA, these behavioral alterations were associated with alterations in BLA KOP function. Specifically, while GABA transmission in BLA pyramidal neurons from non-stressed adolescent males responded variably (potentiated, suppressed, or was unchanged) to the KOP agonist, U69593, U69593 significantly inhibited BLA GABA transmission in the majority of neurons from stressed adolescent males, consistent with the observed anxiogenic phenotype in stressed adolescent males. This is the first study to demonstrate stress-induced alterations in BLA KOP function that may contribute to stress-induced social anxiety in adolescent males. Importantly, these findings provide evidence for potential KOP-dependent mechanisms that may contribute to pathophysiological interactions with subsequent stress challenges.
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Affiliation(s)
- E I Varlinskaya
- Department of Psychology, Center for Development and Behavioral Neuroscience, Developmental Exposure Alcohol Research Center, Binghamton University, Binghamton, NY 13902, United States
| | - J M Johnson
- Department of Psychology, Center for Development and Behavioral Neuroscience, Developmental Exposure Alcohol Research Center, Binghamton University, Binghamton, NY 13902, United States
| | - K R Przybysz
- Department of Psychology, Center for Development and Behavioral Neuroscience, Developmental Exposure Alcohol Research Center, Binghamton University, Binghamton, NY 13902, United States
| | - T Deak
- Department of Psychology, Center for Development and Behavioral Neuroscience, Developmental Exposure Alcohol Research Center, Binghamton University, Binghamton, NY 13902, United States
| | - M R Diaz
- Department of Psychology, Center for Development and Behavioral Neuroscience, Developmental Exposure Alcohol Research Center, Binghamton University, Binghamton, NY 13902, United States.
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Anderson RI, Agoglia AE, Morales M, Varlinskaya EI, Spear LP. Stress, κ manipulations, and aversive effects of ethanol in adolescent and adult male rats. Neuroscience 2012; 249:214-22. [PMID: 23276674 DOI: 10.1016/j.neuroscience.2012.12.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 12/11/2012] [Accepted: 12/18/2012] [Indexed: 12/16/2022]
Abstract
Elevated ethanol use during adolescence, a potentially stressful developmental period, is accompanied by insensitivity to many aversive effects of ethanol relative to adults. Given evidence that supports a role for stress and the kappa opioid receptor (KOR) system in mediating aversive properties of ethanol and other drugs, the present study assessed the role of KOR antagonism by nor-binaltorphimine (nor-BNI) on ethanol-induced conditioned taste aversion (CTA) in stressed (exposed to repeated restraint) and non-stressed male rats (Experiment 1), with half of the rats pretreated with nor-BNI before stressor exposure. In Experiment 2, CTA induced by the kappa agonist U62,066 was also compared in stressed and non-stressed adolescents and adults. A highly palatable solution (chocolate Boost) was used as the conditioned stimulus (CS), thereby avoiding the need for water deprivation to motivate consumption of the CS during conditioning. No effects of stress on ethanol-induced CTA were found, with all doses eliciting aversions in adolescents and adults in both stress conditions. However, among stressed subjects, adults given nor-BNI before the repeated stressor displayed blunted ethanol aversion relative to adults given saline at that time. This effect of nor-BNI was not seen in adolescents, findings that support a differential role for the KOR involvement in ethanol CTA in stressed adolescents and adults. Results from Experiment 2 revealed that all doses of U62,066 elicited aversions in non-stressed animals of both ages that were attenuated in stressed animals, findings that support a modulatory role for stress in aversive effects of KOR activation. Collectively, these results suggest that although KOR sensitivity appears to be reduced in stressed subjects, this receptor system does not appear to contribute to age differences in ethanol-induced CTA under the present test circumstances.
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Affiliation(s)
- R I Anderson
- Center for Development and Behavioral Neuroscience, Department of Psychology, Binghamton University, 4400 Vestal Parkway East, Binghamton, NY 13902-6000, USA.
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Petrov ES, Varlinskaya EI, Spear NE. The surrogate nipple technique in the rat provides a useful animal model of suckling in bottle-feeding circumstances: reply to Blass (2002). Physiol Behav 2003; 78:813-7. [PMID: 12782239 DOI: 10.1016/s0031-9384(03)00038-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Cheslock SJ, Varlinskaya EI, High JM, Spear NE. Higher Order Conditioning in the Newborn Rat: Effects of Temporal Disparity Imply Infantile Encoding of Simultaneous Events. Infancy 2003. [DOI: 10.1207/s15327078in0402_01] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Abstract
The present study examined responsiveness of newborn rats to a surrogate nipple providing fluids with basic tastes (sweet, sour, bitter and salty) and assessed the effects of this first gustatory experience on subsequent responding to the nipple itself (empty nipple) or the nipple providing water. Responsiveness (attachment to and ingestion from a surrogate nipple providing saccharin, saline, quinine or ammonium chloride) was compared with that toward a nipple providing water. Compared to water, saline and quinine significantly reduced attachment to and ingestion from the nipple, while saccharin and milk significantly increased attachment behavior. Ammonium chloride increased attachment but not ingestive behavior. Suckling experience with saline, quinine and ammonium chloride attenuated both attachment and ingestive behaviors when subjects were tested 1 h later with an empty surrogate nipple or a nipple providing water. Experience with saccharin and milk (but not water) increased both measures. The data suggest that in newborn rats, as early as a few hours after birth, mechanisms of gustatory detection have control over suckling behavior. Initial experience with the tastants available from the nipple in the first suckling episode may alter further responsiveness to the nipple itself, mediated perhaps by mechanisms of appetitive and aversive conditioning.
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Affiliation(s)
- M E Nizhnikov
- Center for Developmental Psychobiology, Binghamton University-SUNY, Binghamton, NY 13902-6000, USA.
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Petrov ES, Varlinskaya EI, Spear NE. Self-administration of ethanol and saccharin in newborn rats: effects on suckling plasticity. Behav Neurosci 2001; 115:1318-31. [PMID: 11770062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Responsiveness to a surrogate nipple providing water, saccharin, 5% ethanol, or 10% ethanol was tested in newborn rats naive to suckling (3-5 hr old) on Postnatal Day (P) 0 and in older neonates with regular suckling experience on P1 or P2. At all ages, pups demonstrated greater nipple attachment for saccharin or 5% ethanol than for water. Intake of saccharin and 5% ethanol was high in newborns, far exceeding that of water. At P1 and P2, pups exhibited a preference for saccharin, but not for 5% ethanol. Preexposure to a nipple providing ethanol or saccharin (but not a nipple alone or fluids alone) increased subsequent responsiveness toward an empty surrogate nipple (no fluid), both 1 hr and 24 hr after preexposure. Although, during preexposure, pups responded most positively to the nipple providing saccharin, the longest time spent on an empty nipple was observed in pups preexposed to 10% ethanol.
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Affiliation(s)
- E S Petrov
- Center for Developmental Psychobiology, Department of Psychology, State University of New York at Binghamton, 13902-6000, USA.
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Cheslock SJ, Varlinskaya EI, Petrov ES, Silveri MM, Spear LP, Spear NE. Ethanol as a reinforcer in the newborn's first suckling experience. Alcohol Clin Exp Res 2001; 25:391-402. [PMID: 11290850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND Recent evidence suggests that human infants prefer alcohol-flavored milk when fed through a bottle. Animal models also indicate a surprising predisposition for neonatal and infant rats to voluntarily and willingly ingest ethanol. These findings suggest high susceptibility to the reinforcing properties of ethanol early in ontogeny. METHODS A surrogate nipple technique-a highly effective tool for investigation of the reinforcing properties of different fluids-was applied in the present study. Tests of ethanol reinforcement were accomplished in terms of two basic paradigms of Pavlovian conditioning. In one paradigm, the conditioned stimulus (CS) was the surrogate nipple, and in the other, the CS was a novel odor. RESULTS Newborn rats showed sustained attachment to the nipple providing 5% ethanol, and later reproduced this behavioral pattern toward the empty nipple (CS alone). Ingestion of ethanol yielding appetitive reinforcement was accompanied by detectable blood alcohol concentrations, with most in the range of 20-30 mg/dl. The reinforcing efficacy of ethanol was also confirmed in the classical olfactory conditioning paradigm: following pairing with intraoral ethanol infusions, the odor (CS) alone elicited sustained attachment to an empty nipple. Females showed better olfactory conditioning with low concentrations of ethanol, whereas males were effectively more conditioned to high concentrations. Although there were no reinforcing consequences of intraperitoneally injected ethanol [as an unconditioned stimulus (US)] when a neutral odor was the CS, when paired with ingestion of water from a nipple, the injection of ethanol had a reinforcing effect. CONCLUSIONS The present series of experiments revealed ethanol reinforcement in the newborn rat. Two varieties of Pavlovian conditioning established that ethanol can serve as an effective US, and hence reinforcer, in such a way as to increase the approach and responsiveness toward stimuli paired with that US, indicating appetitive reinforcement.
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Affiliation(s)
- S J Cheslock
- Center for Developmental Psychobiology, Department of Psychology, Binghamton University, SUNY, New York 13902-6000, USA
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Varlinskaya EI, Spear LP, Spear NE. Acute effects of ethanol on behavior of adolescent rats: role of social context. Alcohol Clin Exp Res 2001; 25:377-85. [PMID: 11290848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND First experiences with alcohol in humans occur predominantly in adolescence, and to a large extent the attractiveness of alcohol at this age is based on its ability to facilitate certain forms of social behavior (social facilitation). Adolescence is strongly marked by a focus on peer relationships, and the social nature of the situation plays an important role in responsiveness to alcohol. Peer-directed social activity of adolescent rats may be a valuable experimental model for the study of ethanol-induced changes in social behavior and assessment of the role of the social context in responsiveness to ethanol. METHOD In the present study we used a modified dyad social interaction test to characterize acute effects of ethanol on different forms of social behavior (social investigation, contact behavior, and play) and social motivation (preference/avoidance of a peer) in adolescent rats. Ethanol effects on behavior directed toward a peer were compared with those induced by exposure to an inanimate novel object. RESULTS In the social context, the effects of ethanol were dose-dependent and biphasic. Low doses of ethanol (0.25-0.75 g/kg) produced apparent social facilitation (increased social activity and enhanced social preference), whereas higher doses (3 and 4 g/kg) caused social inhibition (decreased social activity and avoidance of a peer). This pattern was not observed for a nonsocial stimulus: Although overall activity in the nonsocial context was suppressed by 2 and 3 g/kg of ethanol, 0.5 g/kg of ethanol did not activate overall activity directed to the inanimate object. CONCLUSIONS These findings demonstrate that the social nature of the testing situation plays an important role in responsiveness to alcohol in adolescence, especially to its activating effects. The results suggest also that the study of ethanol effects on social behavior of adolescent rats may be an effective tool for the study of adolescent alcohol use and abuse.
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Affiliation(s)
- E I Varlinskaya
- Center for Developmental Psychobiology, Department of Psychology, Binghamton University, New York 13902-6000, USA.
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Abstract
The present study examined the role of endogenous activity at mu and kappa opioid receptors in attachment to and ingestion of milk from a surrogate nipple in cesarean-delivered newborn rats prior to regular suckling experience. Selective opioid antagonist drugs were injected into the cisterna magna (IC administration) or lateral ventricles (ICV administration). Blockade of endogenous activity at mu opioid receptors by IC administration of the selective antagonist CTOP reduced attachment time and markedly increased disengagements from the nipple. CTOP also increased the intensity of suckling measured as milk intake per min attached to the nipple, when milk was available from the nipple in a free-access regime, and enhanced intake when milk was infused through an intraoral cannula aside from the suckling context. The ICV administration of the selective kappa antagonist nor-BNI considerably increased latency to grasp the surrogate nipple, while time on the nipple and milk intake were decreased. The presented data suggest that populations of mu and kappa receptor-containing neurons, differentiable by the route of antagonist administration, play an important role in initiation and maintenance of suckling behavior in the newborn rat during its first encounter with the nipple and milk. The kappa opioid system is predominantly involved in the initiation of the newborn's behavior directed toward the nipple providing milk. The role of the mu opioid system seems more complicated: it transforms initial oral grasp responses into sustained attachment to the nipple and maintains the intake of milk at a certain physiological level.
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MESH Headings
- Animals
- Feeding Behavior/drug effects
- Feeding Behavior/physiology
- Female
- Injections, Intraventricular
- Male
- Naltrexone/analogs & derivatives
- Naltrexone/pharmacology
- Narcotic Antagonists/administration & dosage
- Narcotic Antagonists/pharmacology
- Rats
- Rats, Sprague-Dawley/growth & development
- Rats, Sprague-Dawley/physiology
- Receptors, Opioid, kappa/antagonists & inhibitors
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/metabolism
- Somatostatin/analogs & derivatives
- Somatostatin/pharmacology
- Sucking Behavior/drug effects
- Sucking Behavior/physiology
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Affiliation(s)
- E S Petrov
- Center for Developmental Psychobiology, Department of Psychology, Binghamton University-SUNY, Binghamton, New York 13902-6000, USA
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Abstract
The rat fetus exhibits oral grasp responses when presented with an artificial nipple in utero. Preexposure to milk produces a transient decrease in oral grasp responses. The effect of milk on oral grasping is mediated by endogenous activity in brain opioid systems. Specifically, milk triggers mu activity in rostral brain regions and kappa opioid activity in caudal brain regions to decrease oral grasping of the artificial nipple. Reexposure to the artificial nipple after it has been paired with milk during a classical conditioning trial results in a conditioned reduction in oral grasping that is evident when fetuses are reexposed to the nipple. The classically conditioned decrease in oral grasping is mediated by mu opioid activity in rostral brain regions and kappa opioid activity in caudal brain regions. Endogenous opioid systems, activated by exposure to milk and the nipple, may regulate the processing of sensory information during suckling in the rat.
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Affiliation(s)
- E S Petrov
- Laboratory of Perinatal, Neuroethology, Department of Psychology, Binghamton University-SUNY, Binghamton, NY 13902-6000, USA
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Cheslock SJ, Varlinskaya EI, Silveri MM, Petrov ES, Spear LP, Spear NE. Acute effects of ethanol and the first suckling episode in the newborn rat. Alcohol Clin Exp Res 2000; 24:996-1002. [PMID: 10924002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
BACKGROUND In humans, early postnatal experience with alcohol is far from rare and includes exposure to alcohol through breast milk or through the bottle to attain sedative effects (Croce, 1987). Exposure to alcohol though mother's milk alters the infant's suckling behavior. However, acute effects of alcohol on suckling behavior using animal models remain to be investigated. METHODS The present study was designed to examine the effects of neonatal alcohol exposure on attachment to a surrogate nipple and ingestion of milk in rat pups, naive both to suckling and to maternal care. Cesarean-delivered rat pups were pre-exposed to four dosages of ethanol (0, 1, 2, and 3 g/kg intragastrically) and tested 30 min after ethanol administration. RESULTS Suckling behavior was impaired only in pups exposed to a dosage of 3 g/kg of ethanol. Pups in this group demonstrated longer latency to attach followed by less efficient suckling--the pups maintained contact with the nipple but showed decreased ingestion of milk from it. Pups treated with 1 g/kg of ethanol showed the greatest suckling efficiency, ingesting far more milk per minute attached to the surrogate nipple than pups in all other groups. At the same time, nonevoked motor activity was significantly suppressed by all three dosages of ethanol. Blood alcohol levels showed a linear relationship with dose at 30 min postintubation. CONCLUSIONS These findings suggest a dissociation between acute ethanol effects on suckling and overall motor activity, with suckling apparently less sensitive to suppressive and more sensitive to activating effects of ethanol.
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Affiliation(s)
- S J Cheslock
- Center for Developmental Psychobiology, Department of Psychology, Binghamton University-SUNY, New York 13902-6000, USA
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Cheslock SJ, Varlinskaya EI, Petrov ES, Spear NE. Rapid and robust olfactory conditioning with milk before suckling experience: promotion of nipple attachment in the newborn rat. Behav Neurosci 2000; 114:484-95. [PMID: 10883799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
An olfactory conditioning paradigm tested the hypothesis that newborn rats are able to learn about events associated with their first experience with milk as early as 3-5 hr after birth. Exposure to lemon odor (conditioned stimulus, [CS]) paired with intraoral milk infusions (unconditioned stimulus, [US]) resulted in strong conditioning: In the presence of the CS, sustained attachment occurred to an empty nipple as if it provided milk, whereas pups in control conditions showed little attachment. A single CS-US pairing was sufficient for strong conditioning, which was evident with a trace interval as long as 60 s. Conditioning was robust enough to promote attachment to a nipple providing saline, which is aversive to the newborn rat, and comparably strong conditioning occurred with sucrose or saccharin as the US. These findings suggest that olfactory conditioning has the potential to modify suckling behavior.
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Affiliation(s)
- S J Cheslock
- Center for Developmental Psychobiology, Department of Psychology, Binghamton University, New York 13902-6000, USA
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Abstract
The present study investigated 1) the effects of individual and grouped housing on social investigation, social contact behavior, and play behavior in adolescent rats tested with low socially active (grouped) and high socially active (isolated) play partners; and 2) the effects of long-term (8 days) and short-term (24 h) isolation on social behavioral manifestations and social motivation in terms of preference or avoidance of play partners. Social isolation of adolescent rats activated play behavior and social behaviors different from play, but play was predominantly affected under the conditions of this study. Long-term isolation was more effective than short-term, and resulted in greater manifestation of play and social preference. Adolescent rats were able to modify their social behaviors in response to social activity of the play partner: in isolated animals exposed to low socially active group-housed partners, play behavior was transformed into social activities unrelated to play; exposure of group-housed adolescents to high socially active previously isolated partners resulted in an increase of play behavior. Testing that allowed avoidance of social contacts revealed a dissociation between manifestations of play behavior and social motivation: group-housed play partners of isolated animals showed elevated levels of play behavior but a tendency to avoid their isolated pairmates.
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Affiliation(s)
- E I Varlinskaya
- Center for Developmental Psychobiology, Department of Psychology, Binghamton University-SUNY, NY 13902-6000, USA.
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Varlinskaya EI, Petrov ES, Cheslock SJ, Spear NE. A new model of ethanol self-administration in newborn rats: gender effects on ethanol ingestion through a surrogate nipple. Alcohol Clin Exp Res 1999; 23:1368-76. [PMID: 10470980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND Ethanol intake in the context of suckling may have distinct and potentially long-lasting consequences for further responsiveness to and acceptance of ethanol, compared to other, more indirect and less natural ways of ethanol exposure early in ontogeny. METHOD Our findings presented in this paper show that a surrogate nipple technique can be used for the study of early ethanol intake in cesarean-derived rat pups tested before any suckling experience. RESULTS Neonatal rats attached to and voluntary ingested ethanol through the surrogate nipple as early as 4 hr after birth. Moderate concentrations of ethanol (2% and 5%, v/v) promoted substantial initial suckling behavior, including sustained attachment to the nipple. Higher concentrations (10% and 15%) were not effective in sustaining suckling. Females responded less positively to 10% ethanol than did males. High concentrations of ethanol were less effective in eliciting suckling behavior, probably due to the aversiveness of ethanol odor. However, when ethanol was presented in solution with milk, newborn pups attached to the nipple and ingested even 15% ethanol. Contamination of milk with 15% ethanol was more aversive for females than for males. Newborn rat pups demonstrated similar patterns of nipple attachment and ingestive behavior for 5% ethanol and milk. Initial experience with milk in the context of suckling did not prevent further voluntary ethanol ingestion from the same nipple; furthermore, initial exposure to 5% ethanol did not impair subsequent responsiveness to milk. CONCLUSIONS Gender differences in responsiveness or sensitivity to ethanol can be detected in rat pups as early as a few hours after birth. The results suggest a leftward shift in the dose-response curve for females compared with males, indicating that female neonates are more sensitive or more responsive than males to ethanol. The similarity of suckling behaviors produced by moderate concentrations of ethanol and milk suggests a certain unity in their reinforcing mechanisms in the context of the first suckling episode.
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Affiliation(s)
- E I Varlinskaya
- Department of Psychology, Binghamton University - SUNY, New York 13902-6000, USA.
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Petrov ES, Varlinskaya EI, Bregman K, Smotherman WP. Sustained attachment to the nipple in the newborn rat depends on experience with the nipple, milk, and the expression of oral grasping. Behav Neurosci 1999; 113:211-21. [PMID: 10197921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Newborn rats showed mouthing, licking, and oral grasping when presented with a surrogate nipple. These responses changed after the pup expressed an oral grasp response and experienced milk at the nipple. Newborn pups that ingested milk from the surrogate nipple showed brief oral grasp responses and, when tested 1 hr later, showed sustained attachment to an empty surrogate nipple. Contact with the nipple, oral grasping of the nipple, and experience with milk altered subsequent behavioral responses to the nipple. Classical and instrumental conditioning may play a role in transforming brief oral grasp responses into longer oral grasp responses and sustained attachment to the nipple.
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Affiliation(s)
- E S Petrov
- Department of Psychology, Binghamton University, State University of New York, 13902-6000, USA
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Abstract
Localized injections of the mu antagonist CTOP into intracisternal (i.c.) or intracerebroventricular (i.c.v.) sites altered the behavior of 1-day-old rat pups during continuous exposure to an artificial nipple. Blockade of mu opioid receptors by i.c. injection decreased oral responsiveness to the nipple, while blockade of receptors by i.c.v. injection of CTOP increased oral responsiveness. The injection of CTOP into the i.c. site produced a transient reduction in body weight gain in pups suckling from their mother, while injection into the i.c.v. site had no effect. When cesarean-delivered pups were tested prior to suckling, injection of CTOP into the i.c. site increased latency of the first nipple attachment and decreased total time attached to a surrogate nipple providing milk. Injection of CTOP into the i.c.v. site decreased latency to the first nipple attachment. The results indicate that there is a caudal population of opioid receptors that is involved in the initiation of suckling behavior and a rostral population that plays a role in decreasing responsiveness at the nipple.
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Affiliation(s)
- E S Petrov
- Department of Psychology, Binghamton University--SUNY, NY 13902-6000, USA
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Koffman DJ, Petrov ES, Varlinskaya EI, Smotherman WP. Thermal, olfactory, and tactile stimuli increase oral grasping of an artificial nipple by the newborn rat. Dev Psychobiol 1998; 33:317-26. [PMID: 9846235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Caesarean-delivered rat pups tested before any suckling experience show oral grasp responses after stimulation with an artificial nipple. Manipulating the sensory stimuli present at the time of testing alters behavioral responses to the nipple. Specifically, when the nipple is warm, when pups are tested in the presence of amniotic fluid or milk odor, or when pups are tested in the presence of a conspecific, oral grasping of the artificial nipple is increased. Pups respond to the nipple with a shorter latency, show more oral grasp responses, and the individual grasp responses are longer in duration. The experiments suggest that the newborn rat pup exhibits a basic set of behaviors in response to the nipple early in development and that sensory stimuli normally present during the expression of suckling increase oral appetitive behaviors evoked by the nipple.
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Affiliation(s)
- D J Koffman
- Department of Psychology, Binghamton University-SUNY 13902-6000, USA
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Petrov ES, Varlinskaya EI, Smotherman WP. Endogenous opioids and the first suckling episode in the rat. Dev Psychobiol 1998; 33:175-83. [PMID: 9742412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Endogenous activity at opioid receptors affects the appetitive behavior of Caesarean-delivered rat pups during presentation of a surrogate nipple that provides milk. Blockade of opioid receptors by peripheral injection of naloxone has no effect on responses evoked by the surrogate nipple. Similarly, blockade of caudal brain opioid receptors by injection of naloxone into the cisterna magna has no effect on the pup's behavior in response to the surrogate nipple. However, blockade of rostral opioid receptors by injection of naloxone into the cerebral ventricles increases the latency to the first oral grasp response, decreases total time on the nipple, and virtually eliminates ingestion of milk from the surrogate nipple (Experiment 1). Blockade of endogenous opioid activity does not affect responses to a nipple that provides distilled water (Experiment 2) or to an empty surrogate nipple (Experiment 3). These data indicate that during the initial suckling episode endogenous opioids in rostral brain regions affect the pup's behavioral responses to the nipple. The results are consistent with the hypothesis that milk engages opioid systems during the first suckling and that endogenous opioids play a role in early suckling.
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Affiliation(s)
- E S Petrov
- Department of Psychology, Binghamton University-SUNY 13902-6000, USA
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Smotherman WP, Petrov ES, Varlinskaya EI. Experimental study of the first suckling episode: rat pups ingest fluids through a surrogate nipple. Behav Neurosci 1997; 111:1383-94. [PMID: 9438807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The present study reported a new technique in which pups ingested fluids from a surrogate nipple. Cesarean-delivered pups tested before suckling experience showed oral grasp responses and ingested milk from the surrogate nipple. Pups ingested equal amounts of distilled water and milk and rejected saline. After ingesting milk from the surrogate nipple, pups remained attached to an empty surrogate nipple, while pups exposed to distilled water or saline did not show sustained attachment. Brief experience with milk from an oral cannula or from a surrogate nipple elicited sustained attachment to an empty nipple. Pups ingesting milk from a surrogate nipple showed increased intake of water and saline from the nipple when tested subsequently. The surrogate nipple provides a new technique for experimental study of early suckling behavior. The results suggest that initial experiences with milk may reinforce components of early suckling behavior.
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Affiliation(s)
- W P Smotherman
- Department of Psychology, State University of New York at Binghamton, 13902-6000, USA
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Petrov ES, Varlinskaya EI, Smotherman WP. The newborn rat ingests fluids through a surrogate nipple: a new technique for the study of early suckling behavior. Physiol Behav 1997; 62:1155-8. [PMID: 9333212 DOI: 10.1016/s0031-9384(97)00310-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this report we describe an apparatus and procedure that permits a newborn rat pup to ingest test fluids including milk through a surrogate nipple. The surrogate nipple represents a new testing situation for the experimental study of sensory and neurochemical controls of suckling behavior immediately after birth.
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Affiliation(s)
- E S Petrov
- Center for Developmental Psychobiology, Department of Psychology, State University of New York at Binghamton, 13902-6000, USA
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21
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Abstract
Newborn rat pups exhibit oral appetitive behaviors when presented with an artificial nipple. These behaviors include mouthing and licking movements and expression of stereotyped oral grasp response. Caesarean-delivered pups show increased responding to the nipple over the first 5 h after birth that is independent of experience with the nipple. Mimicking maternal licking by stimulating the anogenital region of the newborn rat with a soft paintbrush increases response to the nipple. Pups tested after 24 hr of normal experience respond to the artificial nipple when tested immediately after separation from the mother. However, oral grasping of the nipple is more frequent in 1-day-old pups tested 3 or 5 hr after separation from the mother. Study of behavioral responses to the artificial nipple promises to provide information about sensory and neurochemical controls of the initial suckling episode.
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Affiliation(s)
- W P Smotherman
- Department of Psychology, Binghamton University, SUNY 13902-6000, USA
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22
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Abstract
Pharmacological manipulation of mu opioid receptors located in rostral and caudal parts of the brain produces distinctive changes in perioral responsiveness to nipple-like tactile stimulation in the E20 rat fetus. Blockade of caudal mu opioid receptors by intracistema magna (I.C.) injection of the selective mu antagonist drug CTOP reduces appetitive responses directed toward the artificial nipple. In contrast, blockade of mu opioid receptors in the rostral part of the brain by intracerebroventricular (I.C.V.) administration of CTOP increases fetal responsiveness to perioral cutaneous stimulation including oral capture and grasping of the artificial nipple. This pattern of the results suggests that there are at least two functionally different neuronal populations of mu opioid receptor-containing neurons that are involved in the regulation of the perioral responsiveness in the E20 rat fetus. The caudal part of this mu opioid system increases perioral responsiveness while the rostral part of the system decreases responsiveness to nipple-like perioral stimulation. These findings suggest the possibility that mu opioid systems may play a functional role in regulating neonatal behavior at the nipple.
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Affiliation(s)
- E S Petrov
- Center for Developmental Psychobiology, Department of Psychology, State University of New York at Binghamton, 13902-6000, USA
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23
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Abstract
A single paired presentation of the artificial nipple and milk results in classical conditioning of changes in perioral responsiveness in the E20 rat fetus. This classical conditioning is evidenced by a reduction in responding to perioral tactile stimulation. The results of Experiment 1 confirmed the specificity of milk as an unconditioned stimulus to support classical conditioning. Experiment 2 demonstrated that single-trial classical conditioning with the artificial nipple CS and milk US was possible with a delay of 30 s between nipple and milk presentations. Further, measurements of fetal motor behavior during the delay between CS and US presentations indicated that a single 15-s presentation of the artificial nipple increased movements of the mouth for 30 s after removal of the artificial nipple. Experiment 3 demonstrated that three exposures to the artificial nipple prolonged the expression of mouthing for up to 120 s and made possible single trial classical conditioning with a delay of 120 s between CS and US presentations. The capacity of the fetal CNS to maintain a "behavioral trace" for an ecologically important stimulus, such as the nipple, could have adaptive significance in the early development of motivated behavior.
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Affiliation(s)
- E I Varlinskaya
- Department of Psychology, Binghamton University-SUNY 13902, USA
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24
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Varlinskaya EI, Petrov ES, Smotherman WP. Endogenous AVP systems regulate oral behavior in the rat fetus: neuropeptide systems as ontogenetic adaptations. Behav Neurosci 1996; 110:1148-57. [PMID: 8919017 DOI: 10.1037/0735-7044.110.5.1148] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Pharmacological manipulation of V1 receptors in rostral and caudal brain regions alters perioral responsiveness in the E20 rat fetus. Blockade of caudal V1 receptors or activation of rostral V1 receptors reduces fetal responsiveness to perioral cutaneous stimulation. Activation of caudal V1 receptors or blockade of rostral V1 receptors increases fetal responsiveness to perioral stimulation, including oral capture and grasping of an artificial nipple. These results suggest that V1 receptor-containing neurons regulate perioral responsiveness in the E20 rat fetus and that the 2 populations of neurons exhibit functional differences. The caudal part of the arginine8-vasopressin (AVP) system increases whereas the rostral part decreases responsiveness to different types of perioral stimuli. The neuropeptide AVP may affect suckling behavior immediately after birth by regulating perioral sensory responsiveness.
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Affiliation(s)
- E I Varlinskaya
- Pavlovian Physiological Department, Institute for Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia
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25
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Varlinskaya EI, Petrov ES, Smotherman WP. Endogenous AVP systems regulate oral behavior in the rat fetus: neuropeptide systems as ontogenetic adaptations. Behav Neurosci 1996. [PMID: 8919017 DOI: 10.1037//0735-7044.110.5.1148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pharmacological manipulation of V1 receptors in rostral and caudal brain regions alters perioral responsiveness in the E20 rat fetus. Blockade of caudal V1 receptors or activation of rostral V1 receptors reduces fetal responsiveness to perioral cutaneous stimulation. Activation of caudal V1 receptors or blockade of rostral V1 receptors increases fetal responsiveness to perioral stimulation, including oral capture and grasping of an artificial nipple. These results suggest that V1 receptor-containing neurons regulate perioral responsiveness in the E20 rat fetus and that the 2 populations of neurons exhibit functional differences. The caudal part of the arginine8-vasopressin (AVP) system increases whereas the rostral part decreases responsiveness to different types of perioral stimuli. The neuropeptide AVP may affect suckling behavior immediately after birth by regulating perioral sensory responsiveness.
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Affiliation(s)
- E I Varlinskaya
- Pavlovian Physiological Department, Institute for Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia
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26
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Abstract
This study examined the reinforcing properties of dynorphin A (1-13) in a single-trial classical conditioning paradigm in the E20 rat fetus. Injection of dynorphin into the cisterna magna increased fetal motor activity and reduced facial wiping in a test of perioral cutaneous responsiveness. Dynorphin was effective as an unconditioned stimulus (US) in a classical conditioning paradigm using an artificial nipple conditioned stimulus (CS) and dynorphin A (1-13) US. The association between CS and US was dependent on activity in the kappa opioid system. Re-exposure to the artificial nipple CS after a single pairing of the nipple with dynorphin resulted in conditioned activation of the kappa opioid system. Dynorphin A (1-13) functions as a reinforcer for classical conditioning in the rat fetus after intracisternal or intrahemispheric injection, with the conditioned response depending on route of administration and site of injection.
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Affiliation(s)
- E I Varlinskaya
- Pavlovian Physiological Department, Institute for Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia
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27
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Abstract
Administration of arginine-vasopressin (AVP) into the cisterna magna (IC injection) of the E20 rat fetus increases motor activity and promotes expression of rare patterns of behavior including mouthing, licking, and facial wiping. These effects are mediated by V1 receptors in the brain stem and spinal cord. In this study, AVP-induced changes in motor behavior were measured to characterize interactions within the AVP system and between the AVP and mu-opioid systems in the fetal rat. Injection of AVP into the brain hemispheres (IH injection) diminished the effects of an IC injection of AVP. AVP effects were potentiated by blockade of hemispheric V1 receptors, suggesting that hemispheric V1 receptors inhibit V1 receptor-containing neurons in the brain stem and spinal cord. Intracisternal injection of the mu agonist DAGO suppressed the effects of AVP whereas blockade of mu-opioid receptors in the brain stem and spinal cord with CTOP and activation of mu receptors in the hemispheres with DAGO potentiated the behavioral effects of AVP. The behavioral effects of AVP are mediated by V1 receptors in the brain stem and spinal cord and may be under the inhibitory control of a mu-opioid system localized at the same level of the brain. Facilitation of AVP effects following IH injection of DAGO may involve an inhibition of the inhibitory effects of V1 receptor-containing neurons located in the hemispheres. Interactions between mu-opioid and AVP systems in the caudal and rostral portions of the fetal brain may be based on a common principle.
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Affiliation(s)
- E S Petrov
- Pavlovian Physiology Department, Russian Academy of Medical Sciences, St. Petersburg, Russia
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28
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Abstract
This study examined the reinforcing properties of dynorphin A (1-13) in a single-trial classical conditioning paradigm in the E20 rat fetus. Injection of dynorphin into the cisterna magna increased fetal motor activity and reduced facial wiping in a test of perioral cutaneous responsiveness. Dynorphin was effective as an unconditioned stimulus (US) in a classical conditioning paradigm using an artificial nipple conditioned stimulus (CS) and dynorphin A (1-13) US. The association between CS and US was dependent on activity in the kappa opioid system. Re-exposure to the artificial nipple CS after a single pairing of the nipple with dynorphin resulted in conditioned activation of the kappa opioid system. Dynorphin A (1-13) functions as a reinforcer for classical conditioning in the rat fetus after intracisternal or intrahemispheric injection, with the conditioned response depending on route of administration and site of injection.
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Affiliation(s)
- E I Varlinskaya
- Pavlovian Physiological Department, Institute for Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia
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29
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Varlinskaya EI, Petrov ES, Robinson SR, Smotherman WP. Asymmetrical development of the dopamine system in the fetal rat as indicated by lateralized administration of SKF-38393 and SCH-23390. Pharmacol Biochem Behav 1995; 50:359-67. [PMID: 7617674 DOI: 10.1016/0091-3057(94)00273-l] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The dopamine D1 agonist SKF-38393 and the D1 antagonist SCH-23390 were administered into the left or right cerebral hemisphere of the rat fetus on E21 of gestation. Intrahemispheric (IH) injection of the agonist promoted a large-magnitude increase in fetal motor behavior, which involved movements of the head, limbs, and body trunk. Although no lateral asymmetries were evident in left or right injections of the agonist, IH injection of the antagonist into the fetus's left hemisphere produced more pronounced effects on oral behavior, including mouth, lick, and facial wipe movements. Administration of SCH-23390 into the same hemisphere as SKF-38393 was effective in reversing the behavioral effects of the agonist, with left IH injections showing more immediate and complete blockade of agonist-induced behavioral activation. These data provide evidence for functional asymmetries in D1 receptors of the dopamine system in the term rat fetus.
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Affiliation(s)
- E I Varlinskaya
- Pavlovian Physiological Department, Russian Academy of Medical Sciences, St. Petersburg
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30
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Varlinskaya EI, Petrov ES, Robinson SR, Smotherman WP. Behavioral effects of centrally administered arginine vasopressin in the rat fetus. Behav Neurosci 1994. [PMID: 8037883 DOI: 10.1037//0735-7044.108.2.395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Arginine8 vasopressin (AVP) was administered to rat fetuses on Embryonic Day 20 via intracisternal (IC), intrahemispheric (IH), or intrathecal (IT) injection. The IC administration of AVP promoted a 4-fold increase in motor activity, including the uncommon patterns of mouthing, licking, and facial wiping. The IH injection of AVP had little effect on fetal behavior, but IT injection resulted in pronounced increases in fetal activity, including mouthing, licking, and wiping. The IT administration of a V1 antagonist blocked AVP effects, whereas IH injection potentiated AVP-induced changes in fetal behavior. The IC blockade of V1 receptors suppressed facial wiping to a chemosensory fluid (lemon) and reduced oral grasping of an artificial nipple, whereas IH injection of the V1 antagonist promoted facial wiping responses and increased grasping of the nipple. These data suggest that AVP may play a role in the development of responsiveness to stimuli encountered in the context of suckling.
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Affiliation(s)
- E I Varlinskaya
- Pavlovian Physiological Department, Russian Academy of Medical Sciences, St. Petersburg
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31
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Abstract
The dopamine D1 agonist SKF-38393 and the D1 antagonist SCH-23390 were administered into the central nervous system of the E21 rat fetus via intracisternal (IC) injection. IC injection of SKF-38393 promoted a dose-dependent increase in fetal motor activity, principally including movements of the forelimbs, head, and body trunk. IC injection of SCH-23390 did not affect overall activity, but selectively suppressed forelimb, rearlimb, and head movements and promoted an increase in mouthing, licking, and facial wiping. Administration of SCH-23390 after IC injection of SKF-38393 was effective in completely reversing the behavioral effects of the D1 agonist. These findings suggest that central manipulation of dopamine D1 receptors can have direct and potent behavioral effects in the term rat fetus.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/administration & dosage
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/antagonists & inhibitors
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Behavior, Animal/drug effects
- Benzazepines/administration & dosage
- Benzazepines/pharmacology
- Cisterna Magna
- Dose-Response Relationship, Drug
- Female
- Fetus/drug effects
- Injections
- Pregnancy
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/antagonists & inhibitors
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Affiliation(s)
- E I Varlinskaya
- Pavlovian Physiological Department, Russian Academy of Medical Sciences, St. Petersburg
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32
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Abstract
The kappa opioid agonist U50,488 was administered to E21 rat fetuses via intracisternal (IC), intrahemispheric (IH), or intrathecal (IT) injection. The IC administration of U50,488 promoted a threefold increase in motor activity, which was predominated by movements of caudal regions of the body (rearlimbs, body trunk, and tail). The agonist effect was reversed by IC administration of the selective kappa opioid antagonist nor-binaltorphimine. The IH injection of U50,488 had little effect on fetal behavior, but IT injection resulted in pronounced increases in fetal activity, including rearlimb, trunk, and tail movements. The IT administration of nor-binaltorphimine blocked U50,488 effects, whereas IH injection of the antagonist had little influence on fetal behavior. These findings suggest that kappa opioid receptors located in the spinal cord may play a role in the regulation of fetal motor behavior.
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Affiliation(s)
- E S Petrov
- Pavlovian Physiological Department, Institute for Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg
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33
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Abstract
Arginine8 vasopressin (AVP) was administered to rat fetuses on Embryonic Day 20 via intracisternal (IC), intrahemispheric (IH), or intrathecal (IT) injection. The IC administration of AVP promoted a 4-fold increase in motor activity, including the uncommon patterns of mouthing, licking, and facial wiping. The IH injection of AVP had little effect on fetal behavior, but IT injection resulted in pronounced increases in fetal activity, including mouthing, licking, and wiping. The IT administration of a V1 antagonist blocked AVP effects, whereas IH injection potentiated AVP-induced changes in fetal behavior. The IC blockade of V1 receptors suppressed facial wiping to a chemosensory fluid (lemon) and reduced oral grasping of an artificial nipple, whereas IH injection of the V1 antagonist promoted facial wiping responses and increased grasping of the nipple. These data suggest that AVP may play a role in the development of responsiveness to stimuli encountered in the context of suckling.
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Affiliation(s)
- E I Varlinskaya
- Pavlovian Physiological Department, Russian Academy of Medical Sciences, St. Petersburg
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34
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Smotherman WP, Robinson SR, Varlinskaya EI, Petrov ES, Orlowski M, de Costa BR, Rice KC. Central administration of the endopeptidase 24.15 inhibitor cFP-AAF-pAB suggests dynorphin as the endogenous ligand underlying behavioral effects of milk in the fetal rat. Pharmacol Biochem Behav 1994; 47:715-9. [PMID: 7911578 DOI: 10.1016/0091-3057(94)90178-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Intraoral infusion of milk to the rat fetus promotes opioid activity that results in reduced responsiveness in a behavioral bioassay involving perioral cutaneous stimulation. Intracisternal administration of cFP-AAF-pAB, an inhibitor of endopeptidase 24.15, prolonged the opioid activity induced by milk infusion. Treatment with the selective kappa opioid antagonist nor-binaltorphimine blocked the effect of cFP-AAF-pAB on milk-induced opioid activity, but treatment with the mu antagonist CTOP or the delta antagonist naltrindole did not. These findings imply that milk may exert its effect on fetal behavior by increasing levels of dynorphin in the fetal central nervous system.
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Affiliation(s)
- W P Smotherman
- Department of Psychology, State University of New York at Binghamton 13902-6000
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35
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Miklyaeva EI, Varlinskaya EI, Ioffe ME, Mats VN, Pokazanyeva LN, Kulikov MA. Differences in the recovery rate of a learned forelimb movement after ablation of the motor cortex in right and left hemisphere in white rats. Behav Brain Res 1993; 56:145-54. [PMID: 8240710 DOI: 10.1016/0166-4328(93)90032-l] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
After ablation of the motor cortex contralateral to the preferred limb, rats were forced to use this limb in grasping food out of a horizontal tube by restraining the non-preferred foreleg with a bracelet. In a right-handed rat the motor behaviour is less impaired and the recovery is better after a left hemisphere lesion in comparison with a left-handed rat after a right hemisphere lesion. This difference is primarily the time needed to use the limb in reaching for seed (testperiod 3) and the total time needed for 10 successive seizings of seed (testperiod 5). Surprisingly, the differences in the course of recovery do not correlate with the degree of preoperative limb preference: the initially ambidextrous rate also show the same differences in results of the motor cortex ablation in left and right hemisphere. However, in the group of initially consistent ambidextrous rats, after 10 weeks of tests with a restrained forelimb, the testing under unrestrained free conditions shows a gradual decrease in the induced limb preference and a shift to the use of the foreleg contralateral to the intact hemisphere, while in contrast the initially consistent left- or right-handed rats preserve the limb preference under the unrestrained testing conditions. Therefore the degree of initial preference still influences the choice of limb after motor cortex ablation and intensive training to use the 'damaged' limb.
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Affiliation(s)
- E I Miklyaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow
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36
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Vartanyan GA, Varlinskaya EI, Shatik SV, Tokarev AV, Chernyaev SG, Klement'ev BI. Structural specificity of factors involved in chemical regulation of muscle tone at the spinal level. Bull Exp Biol Med 1989. [DOI: 10.1007/bf00842035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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37
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Varlinskaya EI, Klement'ev BI. Changes in activity of postural asymmetry factors and recovery of motor function after cortical lesions of the left and right hemispheres. Bull Exp Biol Med 1987. [DOI: 10.1007/bf00841886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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38
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Vartanyan GA, Varlinskaya EI. Endogenous neuropeptides in regulation of motor functions of the normal and pathological brain. Hum Physiol 1986; 12:63-73. [PMID: 3527944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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39
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Varlinskaya EI, Rogachii MG, Klement'ev BI, Vartanyan GA. Dynamics of activity of postural asymmetry factor after unilateral injury to the motor cortex. Bull Exp Biol Med 1984. [DOI: 10.1007/bf00804289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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40
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Varlinskaya EI, Obukhova GP, Vartanyan GA. Appearance of postural asymmetry of hind limbs in rats following unilateral colchicine block of axonal transport in corticolumbar projections. Bull Exp Biol Med 1984. [DOI: 10.1007/bf00800810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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41
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Vartanyan GA, Balabanov YV, Varlinskaya EI. Brain chemical factors in the formation of stable readjustments in the central nervous system. Bull Exp Biol Med 1981. [DOI: 10.1007/bf00836347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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