030&4522/W$3.00c 0.00
Neuroscience Vol. 36, No. 3, pp. 773-778, 1990
Pergamon Press plc @ 1990 iBRO
Printed in Great Britain
NEURAL
M~~HAN~~M~ UNDERLYING THE ACTION PRIMER PHEROMONES IN MICE
OF
c-s. Lx,H. Km%,H, SAITO am3K‘SEm apartment
of Physiofogy, Kochi Medical School, Nankoku, Koclri 781i-St, Japan
Abstract---&r
electrophysiological experiments in female mice have provided evidence that electrical stimulation of the accessory olfa~io~ bulb orth~romjc~y excites a s~b~p~~t~o~ of tnberoi~fund~bular arcuate neurons by way of the arny~d~l~. The present study shows that haifofsuch neurons are identified as dopaminergic by examining the effectiveness of infusing 6-hydroxydopamine and 5,7-dihydroxytryptamine locally inta the median eminence in blocking their antidromic response. Further attention is focused on excitatory amino acid receptors within the amygdala and the amygdaloid pathway that mediate the aomssury bulb-induced excitation af tu~rojnf~ndibu~ar arcuate neurons. The excitatory transmissiou was reversibly blocked by in~-~m~~d~a infusion (3nmol) of the excitatory amino and antagonists kynurenic acid, D,L-%amino-5-phosphonovalerate, y-D-~utamylaminomet~ylsulphanat~ and D&-2amino-4-phosphonobuty~ate. Intra-amygdala infusions (3 nmol) of N-methyl-n-aspartab and kainate markedly enhanced the tiring activity of tu~roinf~~dib~ar amuate neurons with excitatory inputs from the accessory buufb, whereas similar in&ious of quisquagate were without e&ct. Intm-stria terminalis infusions of the focal anaesthetic Iignocaine ~rnp~e~~y abolished the excitatory ~osm~ssjon in alI the cells tested. Furthered, tu~roinfundibu~ar am&e neurons stimulated from the accessory bulb were also orthadromically sthnulated from the stria terminalis with a shorter latency. These studies demonstrate that the projections of the accessory olfactory bulb activate excitatory amino acid receptors within the amygdala and s~~uent~y the stria terminalis route, thereby causing excitation of tu~roinfund~buIar dopaminergic amuate neurons. This functional pathway can account for the reproductive effects so far described as a consequence of vomeronasal chemoreception.
The accessory olfactory system originating in the vomeronasal organ is important in a variety of ~hem~sensory primer &I&s including the a~l~ra~~n of @erty, induction of oestrus and pregnancy block in female mice following exposure to male urinary odours (~heromon~s).‘i A considerable body of circumstantial evidence has a~~muIa~ showing that ~b~mosi~~al~ received via the vomeronasai organ may be finally transmitted to tuberoinfundibular (TI) dopaminergic neurons which, in turn, regulate prolactin secretion from the pituitary. Injections of the dopatine agonist bromo~riptine reproduced the actions of male pheromones in female mice with identical timing.2.15.20 Conversely, the blocking of dopaminergic transmission by p&o&de prevented the ~heromonaI action of a strange male in newly mated female mice.j6 The principal output neurons of the accessory olfactory bulb fAc>Bl~ the mitral c&Is, which project directly to the ipsilateral &orticomedial nucfeus of the amygdala,** may utilize glutamate or a closely related substance as a transmitter by analogy with main olfactory bulb mitral celIs3.’ Abbret~iafians:
AOB, accessory olfactory bulb; AP4, D,E.-2% amino-4-phos~ho~obutyric acid, AP5, n,t-2-amino-5 ph~~ho~ovale~c acid; 5,7-DHT, 5,7-djhydroxytryptamine; CAMS, u-n_R~utam~aminom~bvi~I~n~~ acid: NMDA, ~-~~y~-~-a~~~af~ ti-
Neuroscience Vol. 36, No. 3, pp. 773-778, 1990
Pergamon Press plc @ 1990 iBRO
Printed in Great Britain
NEURAL
M~~HAN~~M~ UNDERLYING THE ACTION PRIMER PHEROMONES IN MICE
OF
c-s. Lx,H. Km%,H, SAITO am3K‘SEm apartment
of Physiofogy, Kochi Medical School, Nankoku, Koclri 781i-St, Japan
Abstract---&r
electrophysiological experiments in female mice have provided evidence that electrical stimulation of the accessory olfa~io~ bulb orth~romjc~y excites a s~b~p~~t~o~ of tnberoi~fund~bular arcuate neurons by way of the arny~d~l~. The present study shows that haifofsuch neurons are identified as dopaminergic by examining the effectiveness of infusing 6-hydroxydopamine and 5,7-dihydroxytryptamine locally inta the median eminence in blocking their antidromic response. Further attention is focused on excitatory amino acid receptors within the amygdala and the amygdaloid pathway that mediate the aomssury bulb-induced excitation af tu~rojnf~ndibu~ar arcuate neurons. The excitatory transmissiou was reversibly blocked by in~-~m~~d~a infusion (3nmol) of the excitatory amino and antagonists kynurenic acid, D,L-%amino-5-phosphonovalerate, y-D-~utamylaminomet~ylsulphanat~ and D&-2amino-4-phosphonobuty~ate. Intra-amygdala infusions (3 nmol) of N-methyl-n-aspartab and kainate markedly enhanced the tiring activity of tu~roinf~~dib~ar amuate neurons with excitatory inputs from the accessory buufb, whereas similar in&ious of quisquagate were without e&ct. Intm-stria terminalis infusions of the focal anaesthetic Iignocaine ~rnp~e~~y abolished the excitatory ~osm~ssjon in alI the cells tested. Furthered, tu~roinfundibu~ar am&e neurons stimulated from the accessory bulb were also orthadromically sthnulated from the stria terminalis with a shorter latency. These studies demonstrate that the projections of the accessory olfactory bulb activate excitatory amino acid receptors within the amygdala and s~~uent~y the stria terminalis route, thereby causing excitation of tu~roinfund~buIar dopaminergic amuate neurons. This functional pathway can account for the reproductive effects so far described as a consequence of vomeronasal chemoreception.
The accessory olfactory system originating in the vomeronasal organ is important in a variety of ~hem~sensory primer &I&s including the a~l~ra~~n of @erty, induction of oestrus and pregnancy block in female mice following exposure to male urinary odours (~heromon~s).‘i A considerable body of circumstantial evidence has a~~muIa~ showing that ~b~mosi~~al~ received via the vomeronasai organ may be finally transmitted to tuberoinfundibular (TI) dopaminergic neurons which, in turn, regulate prolactin secretion from the pituitary. Injections of the dopatine agonist bromo~riptine reproduced the actions of male pheromones in female mice with identical timing.2.15.20 Conversely, the blocking of dopaminergic transmission by p&o&de prevented the ~heromonaI action of a strange male in newly mated female mice.j6 The principal output neurons of the accessory olfactory bulb fAc>Bl~ the mitral c&Is, which project directly to the ipsilateral &orticomedial nucfeus of the amygdala,** may utilize glutamate or a closely related substance as a transmitter by analogy with main olfactory bulb mitral celIs3.’ Abbret~iafians:
AOB, accessory olfactory bulb; AP4, D,E.-2% amino-4-phos~ho~obutyric acid, AP5, n,t-2-amino-5 ph~~ho~ovale~c acid; 5,7-DHT, 5,7-djhydroxytryptamine; CAMS, u-n_R~utam~aminom~bvi~I~n~~ acid: NMDA, ~-~~y~-~-a~~~af~ ti-
