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Behavioral effects of vasopressin and oxytocin within the medial preoptic area of the golden hamster
Regulatory Peptides, 12 (1985) 257-260 Elsevier
257
RPT 00414
Short C o m m u n i c a t i o n
Behavioral effects of vasopressin and oxytocin within the medial preoptic area of the golden hamster H. Elliott Albers and Craig F. Ferris Department of Physiology, University of Massachusetts Medical School, 55 Lake Ave., Worcester, MA 01605, U.S.A. (Received 13 June 1985; revised manuscript received 25 July 1985; accepted for publication 25 July 1985)
Summary Arginine-vasopressin (AVP) microinjected into the medial preoptic area (MPOA) induces flank marking behavior, a form of olfactory communication, in the golden hamster. When exposed to the odors of conspecifics flank marking behavior occurs naturally in association wth grooming of the flank gland region. The present study examined whether microinjection of AVP, oxytocin (OXY) and other biologically active peptides into the medial preoptic area (MPOA), lateral cerebroventricle (LV) or the ventromedial or lateral hypothalamus (VMH-LH) would elicit flank gland grooming. Microinjection of AVP and OXY produced 2-3 times more flank gland grooming when microinjected into the MPOA than saline, neurotensin or angiotensin II. Injection of AVP into the LV and VMH-LH produced significantly less flank gland grooming than when injected into the MPOA. vasopressin; oxytocin; behavioral effects; medial preoptic area; hamster
Arginine-vasopressin (AVP) injected into the mammalian CNS has been demonstrated to affect a variety of behaviors (for reviews see Refs. 1,2). In hamsters, an essential role for AVP in flank marking behavior, which is a form of olfactory communication, has been localized within the medial preoptic area (MPOA). Microinjection of AVP, but not other peptides or classical neurotransmitters, into the MPOA Address for correspondence: Dr. H.E. Albers, Dept. of Physiology, University of Massachusetts Medical School, 55 Lake Ave., Worcester, MA 01605, U.S.A. Telephone: 617-856-5695. 0167-0115/85/$03.30 © 1985 Elsevier Science Publishers B.V. (Biomedical Division)
258 triggers intense bouts of flank marking behavior [3,4]. Microinjection of an AVP antagonist into the MPOA inhibits flank marking stimulated by the injection of AVP, and flank marking elicited by the odors of other hamsters [5]. Flank marking is a form of scent marking in which large subaceous glands located on the dorsolateral flank are rubbed against vertical objects [6]. Typically before beginning to flank mark and between bouts of flank marking, hamsters groom the flank gland region by licking and chewing the area until it is wet from saliva. Although AVP within the MPOA appears to be essential for the expression of flank marking behavior it is not known whether an AVP sensitive mechanism within the MPOA is important in the control of grooming of the flank gland region. The present study investigated whether flank gland grooming could be induced by AVP, and other biologically active peptides microinjected into the MPOA, lateral cerebroventricle and the ventromedial-lateral hypothalamus. Nine adult male hamsters anesthetized with sodium pentobarbital were stereotaxically implanted with 26 gauge guide ca nnulas aimed at the medial preoptic area (MPOA). After a 3-day recovery interval each hamster was microinjected with arginine-vasopressin (AVP), oxytocin (OXY), angiotensin II (All), neurotensin (NT) and 0.9% NaC1 (SAL) at 24-h intervals. A within group experimental design was used so that each of the nine hamsters were tested with each peptide and SAL. The order of peptide administered over the 5 days of testing was counterbalanced, so that on day 1 of the experiment animal 1 received AVP, animal 2 received OXY, animal 3 received All, and so on. All peptides were given in a dose of 50 ng dissolved in 50 nl of SAL and injected into unanesthetized hamsters with a 33 gauge needle. Following this initial experiment two other groups of hamsters were prepared with guide cannula aimed at either the lateral cerebrospinal ventricle (LV) (n = 3) or the ventromedial or lateral hypothalamus (VMH-LH) (n = 7). The VMH-LH was selected as a control injection site because studies examining the spread of iodinated peptide microinjected into the hypothalamus [7] suggest that 50-nl injections of AVP into the VMH-LH would not spread from the VMH-LH to the MPOA. Each of these hamsters was subsequently tested with AVP. Following each injection the amount of time spent grooming the flank gland area, as opposed to the face or other body regions, was recorded during a 10-rain test period given approximately during the middle of the hamster's light phase. Throughout the experiments hamsters were maintained on a 12:12 light-dark cycle and provided free access to food and water. Statistical comparisons were made with the one-way classification of the analysis of variance followed by Dunnett's test. Following the experiment the site of injection was histologically evaluated in each hamster. The amount of time spent flank gland grooming during the 10-min test period differed significantly (P < 0.01) depending on the substance injected into the MPOA (Fig. 1). The amount of grooming behavior following injections of All or NT was not found to differ statistically (P > 0.05) from the amount of grooming behavior observed following the injection of SAL. In contrast, both OXY and AVP produced significantly (P < 0.005) more flank gland grooming than SAL. In fact grooming behavior was sufficiently intense following injection of OXY and AVP that the flank region became matted and soaked with saliva. In hamsters injected with AVP, flank
259
MPOA
Z
LV
4
~VMH-LH Z
.~3 o o (.9
r,,
2
Z
5 (.9 Z
0
SAL
All
NT
OXY
~VP
AVP
AVP
Fig. 1. Minutes (5c + S.E.M.) spent flank gland grooming during the 10-min test period following microinjection of saline (SAL), angiotensin II (AII), neurotensin (NT), oxytocin (OXY) and arginine-vasopressin (AVP). Inset key indicates whether AVP was microinjected into the medial preoptic area (MPOA) (n = 9), lateral cerebroventricle (LV) (n = 3) or the ventromedial-lateral hypothalamus (VMH-LH) (n =
7).
gland grooming occurred in association with intense bouts of flank marking. In contrast, only minimal amounts of flank marking were observed following OXY injection, despite the similar amounts of flank gland grooming produced by the two peptides. Less than one minute of the 10-min test period was spent flank gland grooming following injection of AII, NT and SAL. To determine whether the flank gland grooming elicited by AVP injection was the result of its effects within the MPOA, AVP (50 ng/50 nl of SAL) was also injected into the LV and the VMH-LH. One-way analysis of variance revealed a statistically significant difference (P < 0.01) in time spent grooming depending upon the site of AVP injection. Injection of AVP into the LV resulted in 50% less time spent grooming the flank region than following the injection of AVP into the MPOA. AVP injected into the VMH-LH resulted in only basal amounts of grooming. The present study demonstrates that AVP and OXY, but not saline or the vasoactive peptides NT or AII, produce intense bouts of flank gland grooming when injected into the MPOA. This finding is particularly interesting in view of our previous demonstration that AVP and OXY differ significantly in their ability to induce flank marking behavior ([3,8]; Ferris and Albers, unpublished data). Hamsters injected with AVP flank mark up to 80 times in a 10-min test, whereas hamsters injected with OXY flank mark 10 or less times. These observations combined indicate that AVP injected within the MPOA is capable of inducing two contiguous, natural behaviors, i.e. flank gland grooming and flank gland marking. However, OXY whose molecular structure differs from AVP in only 2 of 9 amino acid sequences is capable of inducing only flank gland grooming. In the present study injection of AVP into the LV produced considerable amounts of flank gland grooming, although at levels lower than those seen following injection into the MPOA. It is possible that this grooming resulted from AVP entering the MPOA from the ventricular system. It remains possible however that AVP induces flank gland grooming at CNS sites other than the MPOA. Nevertheless, the present
260 results indicate that g r o o m i n g c a n n o t be nonspecifically induced by A V P injection into any C N S site, since A V P injected into the V M H - L H did not induce flank gland grooming. Other investigators have f o u n d intraventricular injection o f A V P and O X Y to p r o d u c e g r o o m i n g behavior in mice [9,10], and to a lesser extent in rats [10,11]. It is not known, however whether A V P or O X Y are effective in eliciting g r o o m i n g behavior within the M P O A . In these studies all g r o o m i n g behavior was scored, as o p p o s e d to g r o o m i n g directed specifcally at the flank gland region. It would not be suprising, however if little g r o o m i n g was f o u n d to be directed at the dorsal flanks in mice a n d rats, since unlike hamsters, neither species has flank glands. Nevertheless, both A V P and O X Y a p p e a r to p r o d u c e g r o o m i n g in all three rodent species.
Acknowledgements This w o r k was supported by N I H G r a n t s G M - 3 4 7 9 8 and HD-18022.
References 1 Koob, G.F. and Bloom, F.E., Behavioral effects of neuropeptides: Endorphins and vasopressin, Annu. Rev. Physiol., 44 (1982) 571-582. 2 Meisenberg, G. and Simmons, W.H., Centrally mediated effects of neurohypophyseal hormones, Neurosci. Biobehav. Rev., 7 (1983) 263-280. 3 Fen'is, C.F., Albers, H.E., Wesolowski, S.M., Goldman, B.D. and Leeman, S.E., Vasopressin injected into the hypothalamus triggers a stereotypic behavior in golden hamsters, Science, 224 (1984) 521523. 4 Ferris, C.F. and Albers, H.E., Further studies on vasopressin as a chemical messenger in the expression of flank-marking behavior in golden hamsters. Neural and Endocrine Peptides and Receptors '85, Washington, DC, 1985. 5 Ferris, C.F., PoUoek, J., Albers, H.E. and Leeman, S.E., Inhibition of flank-marking behavior in golden hamsters by microinjection of a vasopressin antagonist into the hypothalamus, Neurosei. Lett., 55 (1985) 239-243. 6 Johnson, R.E., Scent marking by male golden hamsters (Mesocricetus auratus). I. Effects of odors and social encounters, Z. Tierpsychol., 37 (1975) 75-98. 7 Ferris, C.F,, Pan, J.X., Singer, E.A., Boyd, N.D., Carraway, R.E. and l_,¢eman, S.E., Stimulation of luteinizing hormone release after stereotaxic microinjeetion of neurotensin into the medial preoptic area of rats, Neuroendocrinology, 38 (1984) 145-151. 8 Albers, H.E., Pollock, J., Simmons, W.H. and Ferris, C.F., A Vl-like receptor mediates the behavioral effects of AVP within the medial preopti¢ area of the hamster brain. Neural and Endocrine Peptides and Receptors '85, Washington, DC, 1985. 9 Delanoy, R.L., Dunn, A.J. and Tintner, R., Behavioral responses to intracerebroventricularly administered neurohypophyscal peptides in mice, Hormones Behav., 11 (1978) 348-362. 10 Meisenberg, G., Short-term behavioural effects of neurohypophyseal hormones: pharmacological characteristics, Neuropharmaeology, 21 (1982) 309-316. 11 Drago, F., Caldwell, J., Pedersen, C.A. and Prange, A.J., Oxytocin and arginine-vasotocin enhance grooming in the rat, Soc. Neurosei. Abstr., 10 (1984) 170.
257
RPT 00414
Short C o m m u n i c a t i o n
Behavioral effects of vasopressin and oxytocin within the medial preoptic area of the golden hamster H. Elliott Albers and Craig F. Ferris Department of Physiology, University of Massachusetts Medical School, 55 Lake Ave., Worcester, MA 01605, U.S.A. (Received 13 June 1985; revised manuscript received 25 July 1985; accepted for publication 25 July 1985)
Summary Arginine-vasopressin (AVP) microinjected into the medial preoptic area (MPOA) induces flank marking behavior, a form of olfactory communication, in the golden hamster. When exposed to the odors of conspecifics flank marking behavior occurs naturally in association wth grooming of the flank gland region. The present study examined whether microinjection of AVP, oxytocin (OXY) and other biologically active peptides into the medial preoptic area (MPOA), lateral cerebroventricle (LV) or the ventromedial or lateral hypothalamus (VMH-LH) would elicit flank gland grooming. Microinjection of AVP and OXY produced 2-3 times more flank gland grooming when microinjected into the MPOA than saline, neurotensin or angiotensin II. Injection of AVP into the LV and VMH-LH produced significantly less flank gland grooming than when injected into the MPOA. vasopressin; oxytocin; behavioral effects; medial preoptic area; hamster
Arginine-vasopressin (AVP) injected into the mammalian CNS has been demonstrated to affect a variety of behaviors (for reviews see Refs. 1,2). In hamsters, an essential role for AVP in flank marking behavior, which is a form of olfactory communication, has been localized within the medial preoptic area (MPOA). Microinjection of AVP, but not other peptides or classical neurotransmitters, into the MPOA Address for correspondence: Dr. H.E. Albers, Dept. of Physiology, University of Massachusetts Medical School, 55 Lake Ave., Worcester, MA 01605, U.S.A. Telephone: 617-856-5695. 0167-0115/85/$03.30 © 1985 Elsevier Science Publishers B.V. (Biomedical Division)
258 triggers intense bouts of flank marking behavior [3,4]. Microinjection of an AVP antagonist into the MPOA inhibits flank marking stimulated by the injection of AVP, and flank marking elicited by the odors of other hamsters [5]. Flank marking is a form of scent marking in which large subaceous glands located on the dorsolateral flank are rubbed against vertical objects [6]. Typically before beginning to flank mark and between bouts of flank marking, hamsters groom the flank gland region by licking and chewing the area until it is wet from saliva. Although AVP within the MPOA appears to be essential for the expression of flank marking behavior it is not known whether an AVP sensitive mechanism within the MPOA is important in the control of grooming of the flank gland region. The present study investigated whether flank gland grooming could be induced by AVP, and other biologically active peptides microinjected into the MPOA, lateral cerebroventricle and the ventromedial-lateral hypothalamus. Nine adult male hamsters anesthetized with sodium pentobarbital were stereotaxically implanted with 26 gauge guide ca nnulas aimed at the medial preoptic area (MPOA). After a 3-day recovery interval each hamster was microinjected with arginine-vasopressin (AVP), oxytocin (OXY), angiotensin II (All), neurotensin (NT) and 0.9% NaC1 (SAL) at 24-h intervals. A within group experimental design was used so that each of the nine hamsters were tested with each peptide and SAL. The order of peptide administered over the 5 days of testing was counterbalanced, so that on day 1 of the experiment animal 1 received AVP, animal 2 received OXY, animal 3 received All, and so on. All peptides were given in a dose of 50 ng dissolved in 50 nl of SAL and injected into unanesthetized hamsters with a 33 gauge needle. Following this initial experiment two other groups of hamsters were prepared with guide cannula aimed at either the lateral cerebrospinal ventricle (LV) (n = 3) or the ventromedial or lateral hypothalamus (VMH-LH) (n = 7). The VMH-LH was selected as a control injection site because studies examining the spread of iodinated peptide microinjected into the hypothalamus [7] suggest that 50-nl injections of AVP into the VMH-LH would not spread from the VMH-LH to the MPOA. Each of these hamsters was subsequently tested with AVP. Following each injection the amount of time spent grooming the flank gland area, as opposed to the face or other body regions, was recorded during a 10-rain test period given approximately during the middle of the hamster's light phase. Throughout the experiments hamsters were maintained on a 12:12 light-dark cycle and provided free access to food and water. Statistical comparisons were made with the one-way classification of the analysis of variance followed by Dunnett's test. Following the experiment the site of injection was histologically evaluated in each hamster. The amount of time spent flank gland grooming during the 10-min test period differed significantly (P < 0.01) depending on the substance injected into the MPOA (Fig. 1). The amount of grooming behavior following injections of All or NT was not found to differ statistically (P > 0.05) from the amount of grooming behavior observed following the injection of SAL. In contrast, both OXY and AVP produced significantly (P < 0.005) more flank gland grooming than SAL. In fact grooming behavior was sufficiently intense following injection of OXY and AVP that the flank region became matted and soaked with saliva. In hamsters injected with AVP, flank
259
MPOA
Z
LV
4
~VMH-LH Z
.~3 o o (.9
r,,
2
Z
5 (.9 Z
0
SAL
All
NT
OXY
~VP
AVP
AVP
Fig. 1. Minutes (5c + S.E.M.) spent flank gland grooming during the 10-min test period following microinjection of saline (SAL), angiotensin II (AII), neurotensin (NT), oxytocin (OXY) and arginine-vasopressin (AVP). Inset key indicates whether AVP was microinjected into the medial preoptic area (MPOA) (n = 9), lateral cerebroventricle (LV) (n = 3) or the ventromedial-lateral hypothalamus (VMH-LH) (n =
7).
gland grooming occurred in association with intense bouts of flank marking. In contrast, only minimal amounts of flank marking were observed following OXY injection, despite the similar amounts of flank gland grooming produced by the two peptides. Less than one minute of the 10-min test period was spent flank gland grooming following injection of AII, NT and SAL. To determine whether the flank gland grooming elicited by AVP injection was the result of its effects within the MPOA, AVP (50 ng/50 nl of SAL) was also injected into the LV and the VMH-LH. One-way analysis of variance revealed a statistically significant difference (P < 0.01) in time spent grooming depending upon the site of AVP injection. Injection of AVP into the LV resulted in 50% less time spent grooming the flank region than following the injection of AVP into the MPOA. AVP injected into the VMH-LH resulted in only basal amounts of grooming. The present study demonstrates that AVP and OXY, but not saline or the vasoactive peptides NT or AII, produce intense bouts of flank gland grooming when injected into the MPOA. This finding is particularly interesting in view of our previous demonstration that AVP and OXY differ significantly in their ability to induce flank marking behavior ([3,8]; Ferris and Albers, unpublished data). Hamsters injected with AVP flank mark up to 80 times in a 10-min test, whereas hamsters injected with OXY flank mark 10 or less times. These observations combined indicate that AVP injected within the MPOA is capable of inducing two contiguous, natural behaviors, i.e. flank gland grooming and flank gland marking. However, OXY whose molecular structure differs from AVP in only 2 of 9 amino acid sequences is capable of inducing only flank gland grooming. In the present study injection of AVP into the LV produced considerable amounts of flank gland grooming, although at levels lower than those seen following injection into the MPOA. It is possible that this grooming resulted from AVP entering the MPOA from the ventricular system. It remains possible however that AVP induces flank gland grooming at CNS sites other than the MPOA. Nevertheless, the present
260 results indicate that g r o o m i n g c a n n o t be nonspecifically induced by A V P injection into any C N S site, since A V P injected into the V M H - L H did not induce flank gland grooming. Other investigators have f o u n d intraventricular injection o f A V P and O X Y to p r o d u c e g r o o m i n g behavior in mice [9,10], and to a lesser extent in rats [10,11]. It is not known, however whether A V P or O X Y are effective in eliciting g r o o m i n g behavior within the M P O A . In these studies all g r o o m i n g behavior was scored, as o p p o s e d to g r o o m i n g directed specifcally at the flank gland region. It would not be suprising, however if little g r o o m i n g was f o u n d to be directed at the dorsal flanks in mice a n d rats, since unlike hamsters, neither species has flank glands. Nevertheless, both A V P and O X Y a p p e a r to p r o d u c e g r o o m i n g in all three rodent species.
Acknowledgements This w o r k was supported by N I H G r a n t s G M - 3 4 7 9 8 and HD-18022.
References 1 Koob, G.F. and Bloom, F.E., Behavioral effects of neuropeptides: Endorphins and vasopressin, Annu. Rev. Physiol., 44 (1982) 571-582. 2 Meisenberg, G. and Simmons, W.H., Centrally mediated effects of neurohypophyseal hormones, Neurosci. Biobehav. Rev., 7 (1983) 263-280. 3 Fen'is, C.F., Albers, H.E., Wesolowski, S.M., Goldman, B.D. and Leeman, S.E., Vasopressin injected into the hypothalamus triggers a stereotypic behavior in golden hamsters, Science, 224 (1984) 521523. 4 Ferris, C.F. and Albers, H.E., Further studies on vasopressin as a chemical messenger in the expression of flank-marking behavior in golden hamsters. Neural and Endocrine Peptides and Receptors '85, Washington, DC, 1985. 5 Ferris, C.F., PoUoek, J., Albers, H.E. and Leeman, S.E., Inhibition of flank-marking behavior in golden hamsters by microinjection of a vasopressin antagonist into the hypothalamus, Neurosei. Lett., 55 (1985) 239-243. 6 Johnson, R.E., Scent marking by male golden hamsters (Mesocricetus auratus). I. Effects of odors and social encounters, Z. Tierpsychol., 37 (1975) 75-98. 7 Ferris, C.F,, Pan, J.X., Singer, E.A., Boyd, N.D., Carraway, R.E. and l_,¢eman, S.E., Stimulation of luteinizing hormone release after stereotaxic microinjeetion of neurotensin into the medial preoptic area of rats, Neuroendocrinology, 38 (1984) 145-151. 8 Albers, H.E., Pollock, J., Simmons, W.H. and Ferris, C.F., A Vl-like receptor mediates the behavioral effects of AVP within the medial preopti¢ area of the hamster brain. Neural and Endocrine Peptides and Receptors '85, Washington, DC, 1985. 9 Delanoy, R.L., Dunn, A.J. and Tintner, R., Behavioral responses to intracerebroventricularly administered neurohypophyscal peptides in mice, Hormones Behav., 11 (1978) 348-362. 10 Meisenberg, G., Short-term behavioural effects of neurohypophyseal hormones: pharmacological characteristics, Neuropharmaeology, 21 (1982) 309-316. 11 Drago, F., Caldwell, J., Pedersen, C.A. and Prange, A.J., Oxytocin and arginine-vasotocin enhance grooming in the rat, Soc. Neurosei. Abstr., 10 (1984) 170.